Cook sushi rice according to package directions either on the stovetop or in a rice cooker (if you don't have a rice cooker already: they are AMAZING!!!)
Meanwhile, prepare ingredients so all you have to do is assemble your bowls once the sushi rice is done cooking. Mix sriracha and mayo together to make spicy mayo then spoon into a plastic bag and cut a tiny hole at the bottom for drizzling.
Once sushi rice is done cooking, mix it with rice vinegar and sugar, stirring well to combine. Add 1/2 cup rice to each bowl and sprinkle with sesame seeds, then add 1/4 package of shrimp, some cucumber, 1/2 of each avocado, pickled ginger, nori and scallions.
Pour soy sauce overtop to taste, and garnish with more sesame seeds. Drizzle a bit of spicy mayo overtop and serve!