Preparation Stir together milk and bread crumbs in a large bowl. Cook bacon in a 10-inch heavy skillet over medium heat, stirring occasionally, until crisp. Transfer with a slotted spoon to paper towels to drain. Pour off all but 1 tablespoon fat from skillet, then cook onion, garlic, chipotles, cumin, and oregano in skillet, stirring, until onion is softened, about 3 minutes. Add water and cook, stirring and scraping up brown bits, until water has evaporated, about 1 minute. Stir into bread crumb mixture, then add ground meats, egg, parsley, bacon, and 1 teaspoon salt and mix well with your hands. Preheat broiler. Form scant tablespoons of meat mixture into balls and thread 3 balls 1/2 inch apart onto each skewer, arranging skewers on a lightly oiled broiler pan. Broil 3 to 4 inches from heat (do not turn) until browned and cooked through, 8 to 10 minutes. Cooks' note:Meatballs can be formed and skewered, but not cooked, 1 day ahead and chilled.
Preparation Stir together milk and bread crumbs in a large bowl. Cook bacon in a 10-inch heavy skillet over medium heat, stirring occasionally, until crisp. Transfer with a slotted spoon to paper towels to drain. Pour off all but 1 tablespoon fat from skillet, then cook onion, garlic, chipotles, cumin, and oregano in skillet, stirring, until onion is softened, about 3 minutes. Add water and cook, stirring and scraping up brown bits, until water has evaporated, about 1 minute. Stir into bread crumb mixture, then add ground meats, egg, parsley, bacon, and 1 teaspoon salt and mix well with your hands. Preheat broiler. Form scant tablespoons of meat mixture into balls and thread 3 balls 1/2 inch apart onto each skewer, arranging skewers on a lightly oiled broiler pan. Broil 3 to 4 inches from heat (do not turn) until browned and cooked through, 8 to 10 minutes. Cooks' note:Meatballs can be formed and skewered, but not cooked, 1 day ahead and chilled.