Heat the beans and a small splash of water in a small skillet over medium-low heat. Keep warm.
Make the sliders: In a large bowl, combine the beef, beer, grated onion (grate it right over the bowl so the juices fall into the meat), garlic, grill seasoning, chili powder and paprika. Score the mixture into 4 equal portions, and form each portion into 3 patties slightly thinner at the center than at the edges for even cooking and to ensure a flat surface (burgers plump as they cook). Drizzle the patties with EVOO.
Make the guacamole, salsa and spicy sour cream: In a small bowl, mash the avocado flesh with half the red onion, jalapeños, cilantro; all of the lime zest and lime juice, and the garlic. Season the guacamole with salt.