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 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.