Rinse rice in a fine mesh strainer under cold water until the water runs mostly clear.
Combine rice and water in a rice cooker or pot. Cook according to package directions (about 20 minutes for stovetop; let sit covered for 10 minutes after cooking).
In a small saucepan, gently heat the rice vinegar, sugar, and salt just until dissolved (do not boil).
Transfer hot rice to a large bowl or baking dish; drizzle the vinegar mixture evenly over the rice.
Gently fold and fan the rice with a spatula to distribute the seasoning and cool slightly. Keep covered with a damp towel until ready to serve.