Prepare the bamboo rolling mat by wrapping it in plastic wrap. This is not completely necessary but will help cleanup later.
Place nori on the bamboo rolling mat, shiny side down with long side facing you.
Use hands or utensil to spread rice around nori, leaving about 1/2 inch bare at the bottom. If using hands be sure to wet them in cold water first to avoid sticking.
Sprinkle the sesame seeds in an even layer over the rice and press into the rice slightly.
Flip the nori over so the rice side is on the bamboo mat and the bare side faces up.
Line up ingredients in an even line in the center of the nori horizontally across from your point of view, be sure not to overload as it could be difficult to wrap. I made two rolls, one with salmon, tuna, carrot, and cucumber, and another roll with tuna, carrot, cream cheese, and fried onions.
Place your thumbs under the mat. Use your other fingers to hold the ingredients and start to lift the mat.
Continue to pull the mat over the roll, rolling the nori and rice over the ingredients to create the roll itself. Be sure to hold the ingredients in place until the nori is fully over the ingredients. Lift the bamboo and plastic wrap free of the roll as you continue to roll. This recipe says the word roll a lot.
Cup your hands over the mat, gently squeezing the roll into shape as you go and continue to roll until the end of the bamboo mat has been reached.
Use the mat to press the roll into the final desired shape.
Lift the roll off the mat and place it on a cutting board.
Slice the roll into 8 even pieces, be sure to wipe down the knife between cuts with some water to avoid sticking.
Plate the sushi and top with Tobiko and/or fried onion. Dip in spicy mayo or soy sauce and enjoy!