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, jalapeos, cilantro; all of the lime zest and lime juice, and the garlic. Season the guacamole with salt.
In another small bowl, toss the tomatoes with the mustard and the remaining red onion, jalapeos, and cilantro. Season the salsa with salt. In another small bowl, stir together the sour cream, hot sauce, and cumin.
Heat a large skillet or grill pan over medium-high heat. Cook the sliders, flipping them once, 6 minutes for medium (adjust the timing for rarer or more well-done sliders). During the last minute of cooking, top each slider with 2 squares of pepper jack, tenting the pan with aluminum foil, if you like, to help melt the cheese.
Top the roll bottoms with small spoonfuls of refried beans. Place the sliders on the beans and top with some lettuce, guacamole, salsa, spicy sour cream and a sprinkling of olives. Set the roll tops in place. Serve the sliders with any remaining toppings.