In a small bowl, whisk together peanut butter, rice vinegar, soy sauce, honey, lime juice, ginger, sesame oil, garlic, and red pepper flakes. Season to taste with salt and pepper (I like 1 teaspoon salt and 1/2 teaspoon pepper). If the dressing is too thick, thin with water, 1 teaspoon at a time.
Peanut butter: To make homemade peanut butter, add 4 cups roasted peanuts to a high-powered blender or food processor. Pulse the peanuts until they are finely chopped. Process or blend on a low speed for 1 minute continuously, then stop the machine and scrape down the sides. The peanut butter will be dry and gritty. Process or blend on a low speed a second time for 1 minute continuously, then stop the machine and scrape down sides. The peanut butter will start to form a clumpy paste. Process or blend on a low speed a third time for 1 minute continuously, then stop the machine and scrape down sides. The peanut butter will be thick and grainy at this point. Process or blend on a medium speed fourth time for 1 to 2 minutes longer. The peanut butter should be creamy, smooth, and warm.
Rice vinegar: Or substitute apple cider vinegar.
Honey: For a vegan version, substitute agave nectar or maple syrup (the flavor will change).
Yield: This recipe makes 1 cup dressing, enough for 8 servings (2 tablespoons each). 1 recipe of dressing will dress 8-10 cups salad.
Storage: Store covered in the refrigerator and use within 4 days.
Make the dressing your own: Substitute almond butter for the peanut butter, make it creamier with a splash of coconut milk, or dial up the heat with more red chili flakes.