Add rice and water into a rice cooker and cook according to instructions.
Combine rice vinegar, sugar, and salt in a small bowl. Heat in microwave for 1 minute. Stir well until the sugar and salt are dissolved.
When rice is cooked, transfer to and spread over a large plate. Swirl in the vinegar mixture slowly and use a spatula to mix well.
Let rice sit until cool, 15 to 20 minutes.