Cover the sheet of nori in a thin even layer of rice, filling all the way out to the edges. (click for guide)
Flip the sheet of nori over so the rice is face down on a bamboo rolling mat that is wrapped in plastic. (click for guide)
Arrange the fillings (spicy tuna, crispy onion, and avocado) in even lines, 1 inch from the edge along the longer side of the nori sheet. (click for guide)
Drape the salmon slices over the top of the roll, adjust the angle so the salmon spans the entire length of the roll. (click for guide)
Place the plastic-wrapped rolling mat over the top of the roll and press the roll into a consistent shape. (click for guide)
Place the roll on a cutting board and grab your sharpest knife. Optionally, cover the roll with plastic cling wrap. Run the knife under water for a second, then shake off any excess. Cut the roll into 8 equal pieces using a gentile sawing motion with the knife, running the knife under the tap between every 2-3 cuts to prevent sticking. (click for guide)
Plate the roll on your serving dish. Drizzle spicy mayo over the pieces then top with tempura crunch (tenkasu). (click for guide)
Notes
If this is your first time making sushi be sure to check out the Sushi Beginner's Guide before getting started!