Pat the salmon dry with paper towels. Mix 1/2 tbs kosher salt and 1/2 tbs sugar and lightly rub over the salmon on all sides. Place salmon on a plate, cover and refrigerate 10 minutes while you prepare other components (short curing firms texture slightly while keeping sashimi quality).

Prep tuna

Pat the tuna dry. Lightly brush the sides of the tuna with 1 tsp neutral oil so sesame seeds will adhere.

Seed and sear tuna

On a small plate combine white and black sesame seeds. Press the oil-brushed tuna loin into the seeds to coat one long side and the two narrow edges, leaving top and bottom mostly bare. Heat a heavy skillet over high heat until shimmering (about 30–60 seconds). Add 1 tsp neutral oil and immediately add the tuna, sesame-coated side down. Sear 20–30 seconds, pressing gently to ensure good contact; flip and sear the plain side 10–15 seconds for rare center. Remove to a cutting board and rest 2 minutes. Slice into 1/4-inch thick slices against the grain.

Rinse cure and slice salmon

Wipe the cured salmon gently with a damp paper towel to remove excess salt and sugar, then pat dry. Slice salmon into 1/4-inch thin slices on a sharp knife, keeping slices uniform.

Dressings & Sauces

Make ponzu-style dressing: in a small bowl combine 4 tbs gluten-free tamari (or use the 6 tsp set aside from accompaniments if preferred), 1 tsp yuzu or lemon juice, 1 tsp sesame oil, 1 tsp honey (or agave) and 1 tsp grated ginger. Whisk until emulsified and taste; adjust acidity or salt by adding a little more citrus or tamari. Keep chilled until plating.

Prepare dipping sauce: pour remaining tamari (if any) into a small ramekin with 1/2 tsp wasabi paste for guests who want a sharper dip. Stir to combine.

Accompaniments & Garnish

Prepare vegetables and garnishes: thinly slice the cucumber and radishes. Halve and thinly slice the avocado, brush lightly with 1 tsp lime juice to prevent browning. Slice scallions on the diagonal for garnish. Rinse and spin dry microgreens or baby arugula.

Assemble platter: on a large chilled serving board or platter arrange salmon slices fanned in one area and sesame-seared tuna slices in another. Place cucumber slices and avocado slices nearby in small overlapping rows. Scatter radish slices and microgreens between the fish to add color and texture. Sprinkle the scallions lightly over both fish and garnish with remaining white and black sesame seeds if desired.

Add accompaniments: place a small bowl of the ponzu-style dressing and a separate ramekin of tamari-wasabi on the platter. Add a mound of pickled ginger and arrange toasted gluten-free crispbreads or rice crackers at the edge of the platter for scooping. Drizzle 1 tbs extra-virgin olive oil over the microgreens and a light squeeze of the remaining lime over the avocado and salmon just before serving.

Serve: provide small forks or chopsticks and plates. Recommend guests spoon a little ponzu over fish or dip into the tamari-wasabi, and enjoy with the crackers and vegetables.