Using a very sharp, long knife (preferably a sashimi knife), cut the fish into 1/4-inch (6 mm) thick slices on a diagonal. Arrange slices on a chilled plate or platter in two neat rows (one row tuna, one row yellowtail) leaving space between pieces so dressing will coat evenly.

Lightly brush each slice with a thin film of neutral oil to give shine and prevent sticking. Sprinkle the fine sea salt and freshly ground black pepper evenly over both sets of slices.

Make Citrus-Soy Dressing

In a small bowl, whisk together soy sauce, yuzu or lemon juice, mirin, sesame oil, rice vinegar, grated ginger and honey until honey is fully dissolved and mixture is homogenous. Taste and adjust: if too salty add 1/2 tsp water or extra citrus; if too tart add a little more honey. Keep at room temperature.

Assemble & Garnish

Just before serving, spoon or drizzle about 1/2 tablespoon of the citrus-soy dressing across each slice of fish (total dressing used about 3 tbs; reserve any extra for diners). Avoid soaking the fish — a light gloss is ideal.

Scatter thinly sliced scallions and toasted sesame seeds evenly over the tuna and yellowtail. If using jalapeño, place one or two very thin rounds on a few pieces for heat and visual contrast. Add small handfuls of microgreens or mizuna between rows for color and texture.

Place optional accompaniments (pickled ginger, wasabi, cucumber/daikon) on the side of the platter. Serve with lime wedges so diners can add a final squeeze to taste.

Service Suggestions

Serve immediately while fish is fresh and chilled. This dish pairs well with steamed rice, light sake, or a crisp white wine. If not serving immediately, keep fish plated on a chilled surface and cover lightly; consume within 30 minutes for best texture.