Rinse 1 cup of sushi rice under cold water until the water runs clear. Cook the rice according to the package instructions, about 15-20 minutes. In a bowl, fold in 2 tablespoons rice vinegar and 1 tablespoon sugar. Let cool to room temperature.

In a skillet over medium-high heat, add oil. Cook 1 pound of shrimp for 2-3 minutes per side until pink and opaque. Toss cooked shrimp with 2 tablespoons mayonnaise and 1 tablespoon sriracha.

Slice 1 avocado and 1 cucumber into thin strips. Prepare any additional vegetables like bell peppers if desired.

Using a mold, layer sushi rice at the base, press gently. Add shrimp, avocado, and cucumber layers. Repeat until desired height, finishing with sesame seeds.

Remove the mold gently to reveal the layered sushi. Drizzle additional spicy mayo on top and serve with soy sauce for dipping.