Pat the sushi-grade ahi tuna dry with paper towels. Using a sharp knife, dice the tuna into 1/4-inch (6 mm) cubes. Place diced tuna in a chilled bowl and keep refrigerated while you make the marinade.

Make and toss with marinade

In a small bowl whisk together soy sauce, sesame oil, rice vinegar, lime juice, honey, toasted sesame seeds, and crushed red pepper flakes (if using). Add the thinly sliced green onion. Pour the marinade over the diced tuna and gently toss to coat. Marinate in the refrigerator for 5–10 minutes — not longer than 30 minutes to preserve texture and freshness.

Crab & Accents

Prepare crab

Gently fold the lump crab meat with mayonnaise, lemon juice, a pinch of salt, and black pepper in a small bowl. Be careful not to break up the lumps; you want piecey texture. Taste and adjust seasoning — if crab is very sweet, use less lemon.

Crunch & Base

Prep chips and produce

Arrange the tortilla chips on a large serving platter or on individual plates in a single even layer with slight overlap. Dice the avocado just before assembly and toss lightly with a squeeze of lime to slow browning. Scatter the diced cucumber and thin radish slices evenly over the chips to build fresh layers.

Assembly

Spoon small mounds of the crab mixture over clusters of chips, spacing 1–2 tablespoons per cluster so chips don’t become soggy in one spot.

Distribute the marinated ahi tuna evenly over the chips and crab, using a slotted spoon if marinade is excessive so chips remain crisp. Aim for 1–2 tablespoons of tuna per chip cluster.

Dot the platter with diced avocado and scatter pickled ginger and cucumber pieces across the top for brightness and texture.

Drizzle spicy mayo in a thin zigzag across the entire platter (use a squeeze bottle or spoon). Follow with a lighter drizzle of unagi/eel sauce to add sweet-savory contrast. If using wasabi mayo, add tiny dots sparingly for heat.

Finish with a sprinkle of additional toasted sesame seeds, more thinly sliced green onion, and microgreens or cilantro. Serve immediately with lime wedges on the side.

Notes & Serving

Serve immediately to preserve chip crunch. If preparing elements ahead, keep the marinated tuna and crab chilled separately and assemble just before serving. Leftover raw tuna should be consumed the same day and stored chilled; do not keep more than 24 hours.