Bluefin a la mexicana

STEP 1: PREP

Toss red onion with lime juice and set aside. Slice leeks into very fine lengthwise strips, about 2-3 inches long.

STEP 2: MIX

Mix mayo and sriracha; refrigerate. Separately whisk ponzu, oil, garlic, onion powder, chiles, and agave.

STEP 3: LEEKS

Heat oil to 350°F. Stir flour, cornstarch, water, salt, and pepper into a thin batter. Lightly coat leeks and fry in small, loose clusters until golden and crisp. Drain on a paper towel.

STEP 4: PRESS

Slice cold tuna across the grain into roughly 2-inch pieces. Place between parchment sheets and gently flatten with a tortilla press or rolling pin until thin but intact. Keep refrigerated until assembly.

STEP 5: BUILD

Spread tostadas thinly with sriracha mayo and add cucumber, sliced avocado, and bluefin. Lightly brush ponzu mixture onto tuna. Top with marinated red onion, crispy leeks, and toasted sesame.