If you have a sushi mat, make sure to wrap it in plastic before rolling. If you don’t have a mat, no problem– just use plastic wrap.
Place a sheet of nori rough side up on a cutting board. Wet your hands with cold water (it will help prevent the rice from sticking to your hands) and spread it to the edges, leaving a 1” border on the side furthest from you. Make sure not to compact the rice too much or it will become mushy.
For a rice-outside roll, flip the nori over so the rice is facing down. For a rice-inside roll, leave the rice facing up. Rice-inside rolls are recommended for beginners as they are easier to roll and seal.
Place a few pieces of avocado, cucumber, and tuna in a straight line on the side closest to you. Then, sprinkle a few pinches of panko over the fillings.
Starting at the side closest to you, roll the nori around the fillings as tightly as you can.
When you reach the end of the nori without rice, brush it with water and roll to seal. Use a very sharp knife to cut 1” pieces of sushi. Running the knife under cold water (without drying it) can help prevent the rice from sticking to it.
Repeat steps 2-6 with the remaining three rolls. Top with sesame seeds and serve with spicy mayo (below) and/or soy sauce.
Sushi is best served immediately.