In a mixing bowl, combine egg white, milk, bread crumbs, salt, and black pepper. Add chicken and mix well. Shape into 12 meatballs. In a skillet, heat oil over medium heat. Add meatballs and cook until no pink remains in chicken. Remove meatballs from skillet. In same skillet, combine sauerkraut and onions. Stir in rice and water. Add balls and crushed tomatoes. Bring to a boil. Reduce heat and simmer, covered for 30 minutes or until rice is done.