Remove skin from chicken pieces and place in CrockPot; add warm water.
In a small bowl, combine marmalade, teriyaki sauce, red pepper flakes, brown sugar, and dry mustard; stir well.
Pour sauce over chicken.
Sprinkle diced onion evenly over chicken pieces.
Sprinkle dash of freshly ground black pepper over top.
Place lid on CrockPot and cook on HIGH 4 hours or LOW 6 hours, or until chicken is done.