Rinse the rice thoroughly under cold water until the water runs clear. In a medium saucepan, combine the rinsed rice and water, bring to a boil, then reduce the heat to low. Cover and simmer for 15 minutes. Once cooked, remove from heat and stir in the rice vinegar and salt. Cover again and let the rice rest for 10 minutes to absorb the seasoning.

Heat olive oil in a large skillet over medium-high heat. Add the shrimp and cook for 2 to 3 minutes on each side until they turn opaque and are fully cooked. Meanwhile, in a small bowl, mix together soy sauce, rice vinegar, sesame oil, sugar, and sriracha. Pour this sauce over the cooked shrimp, toss to coat evenly, and cook for another minute to let the flavors meld.

Using a round mold or the inside of a clean can, press a layer of the seasoned sushi rice into individual serving glasses or bowls. Next, add a layer of the spicy shrimp mixture on top, gently pressing it down to help it stick. Follow with layers of sliced avocado and julienned cucumber to add freshness and crunch. Finish by sprinkling sesame seeds and fresh cilantro or green onions on top for garnish.

Spicy Shrimp Sushi Stacks can be presented in a variety of ways. Serve individual stacks in separate glasses or bowls for a sophisticated look. Alternatively, assemble everything in a large bowl for a casual family-style meal where guests can serve themselves. Offer soy sauce and pickled ginger on the side to enhance the sushi experience. These stacks also work perfectly as an appetizer, making them a great choice for dinner parties or special occasions.