In a small bowl whisk together the smoked paprika, salt, pepper, cayenne, garlic powder, and mustard powder. Whisk in the honey, apple cider vinegar, and garlic.
Place the chopped onion at the bottom of your slow cooker. Lay the pork shoulder pieces on top of the onion. Pour half the spice mixture over top, then flip the pork pieces over and pour the rest of the spice mixture in.
Cover and cook on high for 5-6 hours or on low for 9-10 hours.
Remove pork pieces from the slow cooker and shred with a fork, removing any large pieces of fat. Return to the slow cooker and stir.
To make the sandwiches, pile the pulled pork on the buns, top with BBQ sauce, coleslaw, and jalapenos, and serve.