Keto Sesame-Ginger Seared Ahi with Cucumber Avocado Salad

Why You’ll Love This Recipe

• Restaurant-style seared tuna at home in 20 minutes.
• Crunchy sesame crust meets silky, ruby-rare center—fresh, bright, and satisfying.
• Keto-friendly, low-carb meal with clean, bold flavors and healthy fats.
• Simple ingredients, minimal cooking, big payoff.

Grocery List

• Produce: English cucumber, avocado, lime, fresh ginger, garlic, scallions, cilantro
• Dairy: None
• Pantry: Sashimi-grade ahi tuna, black sesame seeds, white sesame seeds, coconut aminos, toasted sesame oil, avocado oil, rice vinegar, sea salt, black pepper, garlic powder, red pepper flakes

Full Ingredients

For the Tuna and Sesame Crust

• 2 sashimi-grade ahi (yellowfin) tuna steaks, 6 oz/170 g each, about 1 inch thick
• 2 tbsp white sesame seeds
• 2 tbsp black sesame seeds
• 1/2 tsp sea salt
• 1/4 tsp freshly ground black pepper
• 1/4 tsp garlic powder
• 2 tsp coconut aminos (for brushing)
• 1 tsp toasted sesame oil (for brushing)

For the Coconut-Aminos Ginger Dressing

• 2 tbsp coconut aminos
• 1 tbsp avocado oil
• 1 tsp toasted sesame oil
• 1 tbsp fresh lime juice
• 1 tsp rice vinegar (or apple cider vinegar)
• 1 tsp finely grated fresh ginger
• 1 small garlic clove, very finely minced
• 1/4 tsp red pepper flakes (adjust to taste)
• Optional: 1/4 tsp fish sauce for extra umami

For the Cucumber–Avocado Salad

• 1 English cucumber (about 300 g), thinly sliced into half-moons
• 1 ripe avocado, diced
• 2 tbsp thinly sliced scallions
• 1 tbsp chopped fresh cilantro
• Pinch sea salt, to taste

For Searing & Garnish

• 1 1/2 tbsp avocado oil (for the pan)
• Lime wedges, extra scallions or cilantro, and a pinch of extra sesame seeds for serving

Step-by-Step Instructions

Step 1: Prep tuna and mix the sesame crust

Pat the tuna steaks very dry with paper towels. If time allows, wrap each in a fresh paper towel and chill for 5 minutes; this wicks surface moisture and helps the crust adhere and crisp. In a shallow dish, combine the white sesame seeds, black sesame seeds, sea salt, black pepper, and garlic powder; mix well.

Step 2: Make the coconut-aminos ginger dressing

In a small bowl or jar, whisk together coconut aminos, avocado oil, toasted sesame oil, lime juice, rice vinegar, grated ginger, minced garlic, red pepper flakes, and fish sauce (if using). Taste and adjust lime or salt to your liking. Set aside; whisk again just before using.

Step 3: Toss the cucumber–avocado salad

In a mixing bowl, toss the cucumber with 1–2 tablespoons of the dressing and a pinch of salt. Gently fold in the diced avocado, scallions, and cilantro right before serving so the avocado stays vibrant. Set aside.

Step 4: Coat the tuna in sesame

Brush all sides of each tuna steak with the 2 teaspoons coconut aminos and 1 teaspoon toasted sesame oil. Press the steaks firmly into the sesame mixture, coating all sides, including edges. Shake off any loose seeds.

Step 5: Sear the tuna hot and fast

Heat a heavy skillet (cast iron or stainless) over medium-high heat for 2–3 minutes until very hot. Add the avocado oil; it should shimmer. If you have an infrared thermometer, aim for a 400–450°F (205–230°C) pan surface. Lay the tuna in the pan and sear 45–60 seconds per side for rare, without moving, until the sesame seeds are toasty and fragrant. Briefly sear the edges 10–15 seconds each. Target internal temperatures: 95–100°F (35–38°C) for very rare, 110–115°F (43–46°C) for rare to medium-rare. Reduce heat if the seeds begin to scorch.

Step 6: Rest, slice, and plate

Transfer tuna to a board and rest 1–2 minutes to let the crust set. Slice across the grain into 1/4-inch (6 mm) slices. Mound the cucumber–avocado salad on plates, fan tuna slices over the top, and spoon on remaining dressing to taste. Finish with extra cilantro or scallions, a sprinkle of sesame seeds, and lime wedges for squeezing.

Pro Tips

• Use sashimi-grade tuna for the best flavor and texture; keep it cold until just before searing.
• Dry fish sears better: moisture steams the crust and prevents browning.
• Don’t overcrowd the pan—sear in batches if needed to keep heat high and the crust crisp.
• Cast iron gives the most even, high heat for a toasty sesame crust without overcooking the center.
• For thicker or thinner steaks, adjust by 10–15 seconds per side; pull early—carryover heat is minimal but real.

Variations

• Spicy mayo drizzle: Mix 2 tbsp avocado oil mayo with 1–2 tsp sugar-free sriracha and 1 tsp lime juice; drizzle over the tuna.
• Wasabi-lime: Whisk 1/2 tsp wasabi paste into the dressing for a zippy kick.
• Greens swap: Serve tuna and salad over baby arugula or shredded cabbage for extra crunch and volume.

Storage & Make-Ahead

The dressing can be made 3 days ahead and refrigerated; whisk before serving. The sesame seed blend can be mixed 1 week ahead and stored airtight. Slice cucumber up to 4 hours ahead; add avocado at the last minute. Seared tuna is best right away; leftovers can be chilled in an airtight container up to 24 hours and enjoyed cold in salads. Avoid reheating, which overcooks the center. Do not freeze seared tuna.

Nutrition (per serving)

Approximate: 570 calories; 43 g protein; 37 g fat; 15 g total carbs; 8 g fiber; 7 g net carbs. Values vary by brand and exact absorption of oil.