Using a sharp knife, slice the salmon against the grain into ¼-inch slices, then into strips, and finally dice into ¼-inch cubes. Place in a chilled bowl.

Add sesame oil, mirin, soy sauce, capers, yuzu kosho, and sriracha (or chili crisp) to the bowl. Gently fold to coat the salmon evenly without smashing the cubes.

In a serving ring, layer the diced or mashed avocado on the bottom.

Add a thick layer of the seasoned salmon on top. Remove ring gently.

Finish with lime zest and a spoonful of caviar or tobiko if using. Serve immediately.