Mix the paprika, garlic salt, onion powder, oregano, black pepper, cayenne pepper, and red pepper flakes together in a small bowl. Sprinkle this spice mixture on all sides of the pork loin.
Place the pork loin in a crock pot, then add in the bottle of barbecue sauce and 3/4 cup of water. Cook on low for 8 hours.
When the pork is done, carefully remove it from the crock pot and shred with two forks. It should fall right apart. Return the pork to the crock pot.
Prepare the pineapple slaw by combining the pineapple chunks, diced cucumber, diced onion, and chopped cilantro in a bowl. Squeeze the juice from half a lime onto the slaw, then lightly sprinkle chipotle chili pepper seasoning on top (be careful as this can get hot fast). Stir to combine.
Cut the Italian sandwich rolls in half, lengthwise, and fill the sandwich with pulled pork. Pour extra barbecue sauce on top, as desired.
Top the sandwich with the pineapple slaw.