Rinse 2 cups sushi rice under cold water until the water runs mostly clear
Drain the rice well
Add the rice and 2 1/4 cups water to a rice cooker or pot
Cook the rice according to the rice cooker instructions or bring to a boil, then cover and simmer on low for 15 minutes
Turn off the heat and let the rice rest, covered, for 10 minutes
Mix 1/4 cup rice vinegar, 2 tablespoons sugar, and 1 teaspoon salt until dissolved
Transfer the cooked rice to a large bowl
Gently fold the vinegar mixture into the rice
Fan the rice while mixing to help it cool
Let the rice cool to room temperature before using