Prepare the Ribs:
Start by removing the silver skin (the thin membrane) from the back of the ribs. This helps the seasoning penetrate the meat and results in more tender ribs. Use a paper towel to grip the membrane and pull it off gently.

Make the Dry Rub:
In a small bowl, combine the brown sugar, paprika, garlic powder, onion powder, black pepper, cumin, chili powder, and salt. Stir everything together to create a dry rub mixture.

Season the Ribs:
Rub the dry seasoning mixture all over the ribs, pressing it into the meat so it’s well-coated. Make sure to cover both sides of the ribs. Let the ribs sit for 30 minutes to 1 hour for the flavors to soak in (or refrigerate for several hours or overnight).

Set Up the Slow Cooker:
Pour the apple cider vinegar and water into the bottom of the slow cooker. Lay the seasoned ribs into the slow cooker (cutting them in half if necessary to fit). Arrange the ribs in a circular pattern so they cook evenly.

Slow Cook the Ribs:
Cover and cook the ribs on low for 6-8 hours until tender and easily pull away from the bone.

Apply the Barbecue Sauce:
About 30 minutes before the ribs are done, pour the barbecue sauce over them. Set the slow cooker to high for the last 30 minutes to thicken the sauce and let it caramelize.

Finish and Serve:
Once tender, remove the ribs from the slow cooker. Optional: for a crispy, caramelized finish, sear them briefly in a hot skillet or on the grill. Serve immediately.