Bacon gives these beans a subtle smokiness, and chipotle chilies add both smoke and spice. If you decide to use the optional tequila, save your top-shelf bottle for sipping; any inexpensive tequila worked well here. Offer the beans as a side to any Tex-Mex or Mexican-style main, or use them as a filling in tacos and burritos. Or make a light meal out of them by serving with rice, sour cream and salsa. Refrigerate leftovers in an airtight container for up to three days; when reheating, thin with broth or water to the desired consistency.