Special equipment: A large slow cooker (at least 6 quarts)
For the dry rub: Place the salt, smoked and sweet paprika, onion powder, garlic powder, cumin, black pepper and cayenne (if using) in a small bowl and mix with a fork until well blended.
Sprinkle the ribs with the vinegar and rub into the flesh. Rub the dry rub mixture all over the ribs. (This may be done the night before for extra flavor, and placed in the refrigerator.)
Spray the insert of a large (at least 6 quarts) slow cooker with nonstick spray. Place the ribs in the insert, cutting the racks in half if needed to fit. Pour the beer on the bottom of the insert. Cover and cook on low until the meat is tender but still intact (about 9 hours).
When the ribs are almost cooked, prepare a grill for high heat.
Remove the cooked ribs from the slow cooker, blot any excessive (dripping) moisture and place them on the hot grill. Cook until a nice char is formed, 10 to 15 minutes, coating them with BBQ sauce (if using) as they cook.
This recipe turns amazing ribs into a super-quick meal to prepare! Let the slow cooker do all the work all day, and then just finish them in minutes on the grill. The smoked paprika in the dry rub plus the super-low heat of the slow cooker work together to create a smoky-tender rib that tastes like a lot more work than it is. You may also cook the ribs on high for 4 to 5 hours. And if you don't have a grill, you can still get a decent char by broiling on high for a minute or 2 per side (watch closely as the ribs can burn quickly).