Place pork, Teriyaki sauce, rice vinegar, garlic, and red pepper flakes in crockpot.
Cook on low for 6-8 hours.
Remove meat from the crockpot and shred.
Stir peanut butter into the remaining liquid.
Add sliced peppers, and return meat to crockpot.
Cook approximately 30 minutes until peppers are slightly cooked, but still crisp.
Just before serving, stir in green onion and cilantro.
Can be served over rice, in lettuce wraps, or on top of salad.