In a small bowl stir together the brown sugar, salt, onion powder, garlic powder, smoked paprika, and cayenne pepper.
Sprinkle pork on all sides with spice mixture.
Heat the olive oil in a large Dutch oven until hot but not smoking. Sear pork on all sides until browned.
Pour the beer and beef stock over the pork.. Reduce heat to a low simmer. Add a lid at a vent and allow to cook until pork is very tender and shreds easily, about 4 hours. Remove from the pot, shred using two forks, return to the pot and allow to simmer for 5-10 minutes. Remove meat from the pot with a slotted spoon to drain off excess moisture (reserve braising liquid).
In a separate pot heat 2 tbs olive oil, cook the onions and red pepper until soft, about 4 minutes. Stir in the garlic. Add 1 ½ cups of the pork braising liquid, black beans, kidney beans, tomatoes, chipotle pepper and adobo sauce. Simmer for 20 minutes.
Serve topped with cheddar, cilantro, red onion, tomatoes and pulled pork.