In a 6-quart or larger slow cooker, whisk together the coconut milk, peanut butter, curry paste, fish sauce, coconut sugar, ginger, garlic, and red pepper flakes until smooth.
Add the chicken pieces, squash, red bell pepper, and onion to the slow cooker and stir gently to coat with sauce. The mixture will be very thick. Cover and cook on high for 2 to 3 hours or on low for 5 to 6 hours.
Thirty minutes before you are ready to serve, add the peas. Immediately before serving, stir in lime juice.
Serve over rice with a generous sprinkle of fresh cilantro.
TO STORE: Refrigerate leftovers in an airtight storage container for up to 3 days.
TO REHEAT: Gently rewarm chicken in a deep skillet on the stovetop over medium-low heat or in the microwave.
TO FREEZE: Freeze leftovers in an airtight, freezer-safe storage container for up to 3 months. Let thaw overnight in the refrigerator before reheating.