Mix together salt, pepper, paprika, cumin, and cayenne pepper and add to olive oil. Add garlic, onions, and parsley. Mix together well with a fork. Slowly add beer as it will cause the mixture to foam and bubble slightly.
Pour marinade over the chicken in the zip top bag. Remove as much air as possible from the bag and seal. Turn the bag from side to side to make sure all chicken has been coated with the marinade.
Place the bag flat on a small, rimmed kitchen sheet pan and into the refrigerator. Allow to sit up to 1 hour or overnight for best results, turning the bag over every few hours to keep the chicken coated.