For guacamole, in a small bowl mash avocado. Stir in lime juice; season to taste with salt and black pepper. Cover surface with plastic wrap and refrigerate until ready to serve.

Place torn bread in a food processor bowl or blender container. Cover and process or blend until bread resembles coarse crumbs. Transfer bread crumbs to a large bowl; set aside.

Place cilantro and garlic in the food processor bowl or blender container. Cover and process or blend until finely chopped. Add the beans, chipotle pepper, adobo sauce, and cumin. Cover and process or blend using on/off pulses until beans are coarsely chopped and mixture begins to pull away from side of bowl or container. Add bean mixture to bread crumbs. Add egg; mix well. Shape into four 1/2-inch-thick patties.

Lightly grease the rack of an uncovered grill. Place patties on rack. Grill directly over medium coals for 8 to 10 minutes or until patties are heated through, turning once halfway through grilling.

To serve, top the patties with guacamole and tomato.