Place flour in a shallow bowl. Place breadcrumbs in a separate shallow bowl, and mix with ground black pepper and cayenne pepper. Place eggs and water in a small bowl. One piece at a time, coat the chicken in the flour, the eggs and the bread crumbs, and set aside. Heat oil in a deep fryer to 375 degrees F (190 degrees C). In small batches, fry chicken 6 to 8 minutes, or until golden brown. Remove chicken, and drain on paper towels. In a separate small bowl, combine the mayonnaise, horseradish, sour cream, Worcestershire sauce and mustard. Mix well, and serve with the chicken for dipping.