Cover your bamboo sushi mat with plastic wrap. This will help keep the rice from sticking to it.
Cut the top 1/4 from the nori sheet. This helps to keep each piece of the roll more bite-sized and easier to eat with chopsticks.
Next, place the nori sheet onto the plastic wrap with the shiny side facing down. Then press around 3/4 cup of rice onto the nori sheet in an even layer. Tip: Combine a bowl of water and a splash of rice vinegar and use to wet your hands prior to handling the sushi rice. This will prevent the rice from sticking to your hands.
Evenly sprinkle sesame seeds on your sushi rice.
Gently flip the nori sheet over so the rice is facing down. You will add the filling directly to the nori sheet with the rice on the outside.
Spoon about 1/4 of the spicy tuna mixture onto the nori sheet and spread evenly across the middle of the sheet.
Use the bamboo sushi mat to fold your roll until it's completely enclosed. Once the rice is making contact with the nori sheet, pull back the sushi mat so it doesn't get caught in the sushi. Still using the sushi mat as your guide, finish rolling until the roll is completely wrapped. Then wrap the sushi mat around the roll and gently press, tightening the roll together.Keep in mind that rolling sushi is an art that may take some practice so don’t get frustrated if it doesn’t look perfect your first time. It will get easier the more you do it. Using a sharp knife, cut the roll into 8 pieces. I do this by first cutting the roll in half. Then cutting each half in half. Then cutting each fourth in half. Tip: Be sure to clean and wet the edge of your knife before cutting each roll.
I usually serve with soy sauce and wasabi. Sushi rolls are traditionally served with pickled ginger as well.