Pat beef roast dry with paper towels and place on a baking sheet.
In a food processor pulse the garlic cloves, cilantro and lime juice until chopped fine.
Add chipotle peppers in adobo sauce, tomato paste, cumin, salt, garlic powder, onion powder, black pepper, chili powder, and oregano. Pulse until smooth.
Spread half of the cilantro mixture on top of the roast. Transfer roast to slow cooker with the seasoned side down. Spread remaining cilantro mixture over the uncovered side of roast.
Carefully pour the beer into the slow cooker, around the sides of the roast.
Cover the slow cooker and cook on LOW for 8-10 hours, or on HIGH for 5-6 hours.
About an hour before the roast has finished, gently lift one side of the roast and add the rinsed and drained black beans to the bottom on the cooker.
Serve the roast and beans with the delicious juices.