In a medium bowl, mix the tuna and Sriracha together with a fork, breaking the tuna into small pieces as you mix.
Make sushi rice:
Place the rice in a fine mesh strainer, and rinse until all the cloudy white is gone, and the water runs clear. Drain rice. Combine ½ cup water plus 2 tablespoons vinegar, and set aside. In a separate small bowl, make the dressing by combining 3 tablespoons vinegar, salt, and sugar in a small bowl, and stir until dissolved; set aside.
Rice cooker: Combine the rice and 2 cups water in the bowl of the rice cooker, and cook according to the instructions on your rice cooker.
Stove top: Soak rice in water to cover for 30 minutes; drain. Combine rice and 2 cups water in a saucepan and cover. Place the pan over moderately high heat. When the water boils, reduce the heat and cook for 10 minutes. Turn off the heat and allow the rice to steam undisturbed, without removing the lid, for 10 minutes.
Wet a large bowl, preferably a wooden one, with water. Wipe off excess water with a paper towel. Wet the bowl a second time with vinegar water that you made before. Wipe off any excess water.
Take the rice out of the rice cooker, or saucepan, being careful not to scrape any browned rice off the bottom of the pan. Place the cooked rice in center of the wetted wooden bowl. Allow the cooked rice to cool in the bowl for 10 minutes. Pour the dressing over the rice, and mix the dressing in evenly with a large spoon or rice paddle. While mixing, fan the rice to cool it. The rice is ready to use when it reaches body temperature.
Make creamy sriracha:
Mix all creamy sriracha ingredients (sour cream, sriracha, and sesame oil) in a small bowl.
Make carrot slaw:
Place shredded carrot and jicama in a large bowl and set aside. Combine vinegar, water, and sugar in a small saucepan; bring to a boil. Remove from heat and allow to cool slightly; pour cooled dressing over carrots and jicama. Let stand 15 minutes; drain.
Assemble the rolls:
Wrap the bamboo sushi mat in plastic wrap. Place one sheet of nori shiny side out, and the dull side in on top of the mat. (If you do an inside out roll, put the rice on the shiny side of the nori). The lines of the nori go in the same direction as the rolling mat, so that you are rolling up the sushi with these lines, and not against these lines. With wet hands, grab a small handful of sushi rice and evenly spread across the nori being sure to place the rice all the way to sides of the nori, while leaving a strip at the end of the roll, about ½ to 1-inch. Press the rice down to ensure it sticks to the nori.
Lay a thin line of the spicy tuna on top of the rice, and stack the avocado strips on top of the tuna. This is the point to add the Carrot Slaw if you'll be using that. Be careful not to overfill the roll or it will be difficult to roll and eat.
Holding the mat, gently start rolling the fillings up inside the rice and nori. Gently squeeze the roll to tighten it up. Using your finger, wet the open edge of the nori with a little water. This will help seal the roll shut after rolling it up.
Use the bamboo mat to firm up the shape and compact the roll. Remove the bamboo mat and the plastic wrap from the roll. Dip a very sharp knife in water (to keep the roll from sticking to the knife), and cut the roll in half. Continue cutting the pieces in half until you have 8 pieces.
Sprinkle sesame seeds over the roll. Serve with Creamy Sriracha Sauce if desired.
Notes
And remember, if you’re making this recipe with Island Trollers Albacore Tuna, you don’t want to drain off those tasty juices from the can; they’re the juices from the fish itself, not just plain water or oil. Those juices are loaded with Omega 3s. So, it might feel a little weird not to drain the tuna, but don’t do it.