Rinse the sushi rice under cold water until the water runs clear, transfer to a saucepan, add water, cover, and boil.

Reduce heat to low, simmer for 18-20 minutes until water is absorbed and rice is tender. Remove from heat, keep covered for 10 minutes to steam.

In a bowl, mix rice vinegar, sugar, and salt, then fold into warm rice. Cool slightly.

In another bowl, combine cooked shrimp with sriracha and mayonnaise, mixing until coated.

Layer sushi rice in a mold, followed by spicy shrimp, avocado, and cucumber. Repeat until filled.

Remove the mold carefully to reveal the stack.

Garnish each stack with nori strips and serve immediately with soy sauce or sriracha.