In a medium mixing bowl, combine finely chopped onion, wasabi, black pepper, yuzu sesame dressing, and roasted sesame seeds. Mix until well blended.

Cut the sashimi-grade salmon into bite-sized cubes, and slice the avocado in half, removing the pit and scooping out the flesh.

Gently fold the cubed salmon and sliced avocado into the earlier mixture in the bowl, ensuring not to break apart the delicate pieces.

Carefully transfer the salad to a serving dish or individual plates, drizzling additional dressing on top and garnishing with roasted sesame seeds.