Rinse sushi rice under cold water until clear, then combine with water in a rice cooker. Cook according to instructions, about 15–20 minutes.

Transfer rice to a bowl, season with rice vinegar, sugar, and salt while cooling.

In a bowl, dice sushi-grade tuna, mix with mayonnaise, sriracha, and soy sauce until combined.

In another bowl, mix imitation crab, cream cheese, mayonnaise, and sriracha until smooth.

Place nori on bamboo mat, spread sushi rice, add spicy tuna filling, and roll tightly.

Preheat oven to 400°F. Slice rolls, place on baking sheet, and top with volcano mixture. Bake for 10 minutes.

Let cool slightly before serving warm, garnished with leftover spicy tuna or soy sauce.