Thinly slice the red onion and place in a small bowl or jar. Whisk together rice vinegar, water, sugar and 1/4 tsp salt until sugar dissolves. Pour over onions, press down so all are submerged. Let sit at room temperature at least 10 minutes (can hold in fridge up to 24 hours). Drain just before assembly.

Tallow Chips

Crisp chips

Heat 1 tablespoon beef tallow in a small skillet over medium-high heat until shimmering. If using wonton wrappers, cut into triangles; if using store chips, use as-is. Fry 2–3 pieces at a time, 20–40 seconds per side, until golden and blistered. Remove to a paper towel-lined plate and sprinkle with fine sea salt. Alternatively, lightly brush wonton pieces with melted tallow and bake at 400°F (200°C) on a sheet for 6–8 minutes until golden and crisp.

Citrus Soy Dressing

Make dressing

In a small bowl whisk together 3 tbsp soy sauce, 2 tbsp fresh lime juice, 1 tbsp fresh orange juice, 1 tsp sesame oil, 1/2 tsp honey and 1/2 tsp grated ginger until combined. Taste and adjust acidity or sweetness as needed. Stir in 1 tsp freshly ground black pepper. Reserve.

Chili Aioli

Prepare aioli

In a bowl combine 1/4 cup mayonnaise, 1 tsp sriracha, 1/2 tbsp lime juice, 1/4 tsp grated garlic and 1/4 tsp salt. Mix until smooth. Adjust heat with more sriracha if desired. Transfer to a squeeze bottle or small piping bag for plating.

Tuna Tartare

Prepare tuna

Pat the ahi tuna dry with paper towels. Trim any sinew and cut into a small, even dice (about 1/4 inch). Place diced tuna in a chilled bowl.

Combine tartare

Add the finely diced red onion (2 tbsp), minced cilantro (1 tbsp) and sliced scallion (1 tbsp) to the tuna. Pour 2.5–3 tbsp of the citrus soy dressing over the tuna and gently fold to coat — avoid over-mixing to keep texture. Season lightly with 1/4 tsp salt and 1/4 tsp freshly ground black pepper. Taste and add more dressing or seasoning as needed.

Chill briefly

Cover and chill the tartare in the refrigerator for 5–10 minutes to let flavors meld, but do not chill so long that the tuna becomes cold and loses texture.

Assembly & Finish

Using a round ring mold or spoon, portion the tartare onto chilled plates or a single sharing plate (about 3–4 oz tuna per serving). Top with a few pickled red onion slices and lightly drizzle 1/2 tsp toasted sesame oil over each portion if using.

Dot or pipe small amounts of chili aioli around and over the tartare for bright heat. Sprinkle toasted sesame seeds (1 tsp) over the top and add microgreens or herb garnish.

Arrange tallow chips alongside the tartare for scooping. Serve immediately with lime wedges on the side for squeezing.