In a medium bowl, whisk together the peanut butter, soy sauce, honey, rice vinegar, minced garlic, and minced ginger until smooth. If the sauce is too stiff, add a tablespoon or two of warm water to loosen.
Pat the chicken thighs dry and season lightly with salt and pepper. Arrange them in the slow cooker in a single layer if possible.
Pour the peanut sauce evenly over the thighs, turning any pieces to coat well.
Cooking
Cover and cook on low for 6–8 hours or on high for 3–4 hours. Chicken is done when it reaches 165°F and easily shreds with a fork.
Serving
Optionally transfer the chicken to a skillet and simmer the sauce a few minutes to thicken. Spoon sauce over the chicken and garnish with chopped green onions before serving.
Notes
For a lower-carb option, serve over cauliflower rice or a bed of roasted vegetables. Store leftovers in an airtight container for 3–4 days in the refrigerator.