Whisk together honey, oyster sauce, rice wine, garlic, 5-spice powder, crushed red pepper and salt in a bowl.
Place ribs in slow cooker and cover with sauce, turning ribs to coat. Stand ribs on their side to make them fit, if necessary. Cover and cook on low until meat is tender and falling off the bone, 4 to 5 hours, turning ribs once or twice to allow them to brown.
Transfer ribs to a cutting board and cover with foil to keep warm.
Pour cooking liquid through a fine-mesh sieve into a small pot. Bring to a boil over medium heat and cook until reduced by half, about 5 minutes.
