Prep the vegetables and fruit: Slice the cucumbers in half lengthwise, then cut them into thin julienne strips. Repeat the same process with the mango. Add both to a large bowl along with the shredded imitation crab meat.

Make the spicy mayo dressing: In a small bowl, combine the Japanese mayonnaise, sriracha sauce, soy sauce, and rice vinegar. Stir until smooth and well blended.

Toss everything together: Pour the spicy mayo dressing over the crab, cucumbers, and mango. Gently toss until everything is evenly coated.

Chill the salad: Cover and refrigerate the salad for at least 30 minutes to let the flavors come together.

Garnish and serve: Just before serving, slice the avocado and arrange it next to the salad, not on top. Finish with a sprinkle of sesame seeds and panko crumbs if using. Serve chilled and enjoy this fresh, creamy, spicy crab salad.