Cook the rice and water in a rice cooker. (Alternatively, if you don't have a rice cooker, bring the rice and water to boil over high heat. Reduce heat to low and cover for 15 minutes. Remove the pot from the heat and let stand, covered, for 10 more minutes.)

Fluff the rice with a fork and transfer it to a glass bowl. While the rice is still warm, add the rice vinegar, sugar, and salt and gently stir with a wooden spoon to distribute it evenly.

Let stand until cool.

Set a bowl of water and a towel nearby for your hands.

Lay a half-sheet of nori shiny side down on the bottom edge of the bamboo mat.

Lightly moisten your hands in the water bowl and grab a handful of seasoned rice (about ½-¾ cup). Gently press and spread the rice evenly over the nori, going all the way to the top and side edges, but leaving a 1-inch gap uncovered at the bottom edge. The rice should cover the nori, but should not be too thick - you should be able to see the nori through the rice.

Sprinkle a few pinches of toasted sesame seeds over the rice.

Flip the prepared nori rice-side down, lining the 1-inch uncovered gap up with the edge of the bamboo mat closest to you.

Lay strips of your favorite sushi and/or veggies lengthwise across the middle of the nori.

Use the bamboo mat to roll the bottom edge of the nori over the filling, tucking the nori in to firmly enclose the filling.

Open the mat gently and lay it over the roll again, and firmly roll forward until the sushi is tightly rolled. Roll the sushi roll up in the mat once more, pressing to even out the roll.

Lightly moisten a sharp knife and slice the roll into 8 pieces, using a gentle sawing motion. Optional: top the cut side of each piece of sushi with roe.

Repeat until you've used all of your sushi rice.