Rinse and cook sushi rice according to package instructions. Season the rice with a mixture of rice vinegar, sugar, and salt while it's still warm. Gently mix to distribute the seasoning. Allow the rice to cool to room temperature.

Cut fresh sushi-grade tuna into thin strips or small cubes.

Peel and pit ripe avocados. Cut them into thin slices that are wide enough to cover the width of the nori sheet.

Lay a bamboo sushi rolling mat on a clean surface. Place a sheet of plastic wrap over the bamboo mat. This prevents the rice from sticking to the mat.

Lay a sheet of nori, shiny side down, on the plastic-covered bamboo mat.

Wet your fingers with water to prevent the rice from sticking. Take a handful of sushi rice and gently spread it over the nori, leaving about 1 inch of the top edge of the nori sheet uncovered. Flip the rice side down.

Lay the avocado slices and tuna strips in a single layer over the nori sheet along the bottom edge of the nori.

Lift the bamboo mat's edge closest to you and start rolling the nori over the avocado and tuna. Apply gentle pressure to form a tight roll. When the roll is nearly complete, moisten the top edge of the nori with a bit of water to help seal the roll.

Using a sharp, wet knife with a little bit of cold water, slice the roll into bite-sized pieces. Wipe the knife between cuts to prevent sticking.

Serve with soy sauce, wasabi, and pickled ginger on the side. (optional) Enjoy!