Mix together the rice vinegar, unrefined sugar, and sea salt in a small non-metal bowl. 

Whisk it vigorously for about 2 minutes or until most of the unrefined sugar sea salt has dissolved. Set it aside until ready for use. 

If doubling the batch, store remainders tightly covered in a refrigerator for up to 6 weeks. Allow mixture to reach room temperature before use.

Recipe posted with permission from Vegetarian Sushi Secrets: 101 Healthy and Delicious Recipes.