Season both sides of chicken with lightly with salt and pepper, put into crock pot.
In a small bowl, combine honey, soy sauce, onion, ketchup, oil, garlic and pepper flakes. Pour over chicken.
Cook on low for 3-4 hours or on high 1 ½ to 2 ½ hours, or just until chicken is cooked through. Remove chicken from slow cooker, leave sauce. Dissolve 4 teaspoons of cornstarch in 6 tablespoons of water and pour into slow cooker. Stir to combine with sauce. Replace lid and cook sauce on high for ten more minutes or until slightly thickened.
Cut chicken into bite size pieces, then return to pot and toss with sauce before serving. Sprinkle with sesame seeds and serve over rice or noodles.
You can also sprinkle more red pepper flakes on top if you want more heat.
Notes
To make this a freezer meal:Place all ingredients in a resealable gallon-sized freezer bag. Mix together and zip bag closed. When ready to eat, remove from freezer and thaw in fridge for 24 hours. Spray slow cooker with non-stick cooking spray. Pour contents of bag inside the slow cooker. Cook on low for 3-4 hours or on high 1 1/2 to 2 1/2 hours, or just until chicken is cooked through.