Rinse the rice with cold water. Drain until water turns clear.
In a large pot, pour water and rice. Turn heat to high & cover until boiling. Reduce to medium-high and keep a simmer. Cover for 15 minutes, or until rice absorbs all the liquid.
While the rice cooks, prepare the sushi vinegar by heating vinegar, sugar, and sea salt in a small pan. On medium-high heat, wait until the mixture simmers. Whisk until sugar dissolves.
Once rice is done, pour it in a mixing bowl. Drizzle with vinegar mixture on the bowl. Gently fold the rice with a spatula, until the vinegar is evenly mixed.
Cover mixing bowl with a damp towel, wait until it reaches room temperature. Can be refrigerated for up to 2 days.
