Grease the bottom of a slow cooker with the olive oil. Place the chicken in the slow cooker. Sprinkle the chicken with the paprika and sea salt.

In a small bowl, combine tomato sauce, water, and onion.

Pour the tomato sauce mixture around the chicken (not directly on top of the chicken, so as to not wash off the paprika).

Cover and cook on LOW for 6 hours, or until the meat is fully cooked on the inside.

Serve hot with the sauce formed in the pot and topped with the parsley.