Season the pork with salt, pepper, paprika, and garlic powder. Place the sliced onion in the bottom of a slow cooker and set the pork on top. Whisk barbecue sauce, vinegar, and brown sugar, then pour the mixture over the meat. Cover and cook until the pork is fall-apart tender.

Transfer the pork to a board and shred it with two forks. Remove excess fat if needed, then return the meat to the sauce and stir well. Spoon the warm pulled pork onto slider buns. Add a mound of crunchy coleslaw and a pickle slice if you like a sharp, tangy finish.