Rinse sushi rice in a strainer under cold water, swishing and draining until the water runs nearly clear.

Combine rinsed rice and 2 cups water in a heavy-bottomed saucepan. Bring to a boil over medium-high heat, then cover and reduce to low. Simmer for 18 minutes. Remove from heat and let sit, covered, for 10 minutes.

While rice rests, warm vinegar, sugar, and salt in a small pan over low heat until dissolved. Turn the hot rice into a wide bowl, slowly pour the vinegar mixture over it, and fold in with a cutting motion while fanning to cool the rice.

Continue folding and fanning for about 5 minutes until the rice is just warm and glossy. Cover with a damp towel until ready to use.