Cut the nori sheets: Using a 6 ½ inch round bowl or plate, place over a nori sheet and use a clean razor or X-acto knife to cut the nori sheet into 6 ½ inch a circle. Repeat for the other 3 nori sheets and set aside.

Make the sushi rice: Cook the sushi rice according to the package instructions. Bring to room temperature in a wooden bowl.

Make the aioli sauce: In a small bowl, whisk together the mayonnaise and Sriracha sauce. Set aside.

Make the tacos:

1. Cube the salmon and tuna filets into even ½-inch cubes. Mix the fish together and set aside.
2.  Place each nori sheet into a taco holder and spoon the sushi rice into each taco ¼ of the way up. Layer the tacos with the fish and divide the toppings into two different tacos.
3. Taco #1: From the bottom layer up: rice, fish, avocado slices, black sesame seeds, a dollop of wakame seaweed on top, and garnish of chopped green onions. Drizzle of sriracha aioli.
4. Taco #2: From the bottom layer up: rice, fish, avocado slices, toasted sesame seeds, black roe, and garnish of chopped green onions.

Makes 4 large tacos.