Bring water to a boil. Stir in rice. Reduce heat to low, cover, and simmer until liquid is absorbed, about 20 minutes. Let cool and stir in rice vinegar.
Peel kani sticks by hand into thin strips.
In a small bowl, combine mayonnaise, sriracha, and soy sauce.
In a medium bowl, combine kani strips, mango, cucumber, and avocado. Add mayonnaise mixture and toss gently to combine.
Spray a ring mold with nonstick cooking spray. Place it on a plate and fill with rice. Pack rice down and lift off ring. (If you don’t have a ring mold, form a ball of rice in your hands and pat it down onto the plate.). Next, layer the kani salad over the rice.
Garnish with additional mango and dot the plate with sriracha sauce.
Notes:
For the presentation in the photo, cut the avocado, mango, and cucumber into long strips.