Arrange chicken in 6-quart slow cooker. Season with salt, pepper, and pepper flakes.
Combine sauce ingredients and pour over chicken. Cover and cook on low heat for 4-5 hours, or until chicken is cooked through (160-165F.)
Garnish with green onion and sesame seeds if desired. Serve over rice.
For crispy skin, broil your chicken until golden. You can also do this before placing into the slow cooker but I find the final broiling to yield great results.If you like, you can remove all the meat after cooking and throw it into a big batch of rice or use it for sandwiches and wraps.