Rinse the rice if you need to (see notes above) and combine in a pot with the water. Cover. Bring to boil. Reduce to simmer for 20 minutes. At 20 minutes, turn off the heat, but allow the rice to sit in the pot 5 minutes longer.
Meanwhile, dissolve the sugar and salt in the vinegar.
When the rice is done, spread onto a platter and mix in the vinegar (see above text for tips, or watch the video!). Allow to cool to room temperature.
Place a sheet of nori smooth side down, longer edge facing you.
Spread 1/2 cup rice over the nori, leaving a 1″ border along the top. Wet your fingertips to aid in spreading the rice without sticking to your hands.
Arrange fillings in a line down the center of the rice.
Roll up tightly.
Wet the 1″ nori border lightly with water and finish rolling. Set aside, seam side down while you make the rest.
Cut each roll into 8 pieces, using a sharp knife and wiping it with a wet towel between each slice.
Serve with condiments of choice.
To double this recipe: Cook 2 cups sushi rice in 2 1/2 cups water. Double the vinegar mixture like this: 1/2 cup rice vinegar 1 tablespoon sugar 1/2 teaspoon salt