For easy clean-up, use a cooking liner in your slow cooker.
Combine the salt, pepper, brown sugar, garlic powder, onion powder, and smoked paprika in a small bowl.
Flip the ribs bone-side up and use a knife to loosen the membrane, then pull the membrane off.
Rub the spice blend on both sides of the ribs.
Stand the ribs up in a 6-quart slow cooker, coiling them to fit. Cover and cook on low until tender, 6 hours.
Preheat the broiler and line a baking sheet with foil. Transfer the ribs to the baking sheet. Brush both sides with barbecue sauce and broil until dark and bubbly.