Add the creamy peanut butter, rice vinegar, and soy sauce to a small mixing bowl. Whisk until all ingredients are completely incorporated and smooth.
Garnish with chopped peanuts if desired.
Notes
You can add 1-2 tablespoons of water if your sauce is a bit too thick. Be careful, you do not want the sauce to be watery. You want the sauce to be thick enough to coat the back of a spoon.