Preheat the oven to 300 degrees F. Place each rack of ribs on a doubled sheet of aluminum foil.
In a bowl, whisk together the salt, paprika, mustard, garlic powder, pepper, onion powder and chipotle chili powder. Rub the mixture all over both sides of the ribs, then wrap the ribs up in the aluminum foil. Place the racks on a baking sheet and put them on the center rack in the oven.
Bake for 2 1/2 hours.
After 2 1/2 hours, gently pour the juice in the foil packets into a large bowl or measuring cup. The ribs are fine and ready to eat now, but they get DELISH if you throw them on the grill. To do this, whisk in 3 to 4 tablespoons of blood orange BBQ sauce into the juice from the ribs.
Heat the grill to the highest setting and remove the ribs from the foil. Once the grill is hot, place the ribs on the grill and cook for 10 to 12 minutes, until they are charred and slightly crisp on the outsides, basting and rubbing the juices/BBQ sauce mixture on top. Let cool slightly before slathering and serving with lots of blood orange BBQ sauce. Serve alongside the avocado butter greens!
Another option to not grilling: heat the broiler in your oven to the highest setting and baste the ribs with the juices/sauce mixture. Keep the rack in the center of your oven and broil for 2 to 3 minutes per side, basteing th ribs in between.