Rinse the pork belly and pat dry. Transfer to a resealable 2-gallon plastic bag. To make the spice rub, mix the kosher salt, pink salt, brown sugar, honey, red pepper flakes, paprika and cumin in a bowl. Coat the pork belly all over with the mixture.
Close the bag and refrigerate 7 to 10 days, flipping once a day, until the pork belly feels firm. It should take 7 days for a thin belly that is about 11/2 inches thick, longer for a belly that's 2 to 3 inches thick.
Remove the pork belly from the bag, rinse thoroughly and pat dry. Refrigerate the belly on a rack, uncovered, 48 hours.
Set up your smoker according to the manufacturer's instructions using applewood chips, and set to 200 degrees F. Smoke the pork belly 3 hours, or until the bacon reaches an internal temperature of 150 degrees F.
Remove the rind (optional), then slice and cook as desired. To store, wrap the bacon in plastic wrap and refrigerate up to 1 week or freeze up to 2 months.
Pink curing salt is a mix of salt and sodium nitrite. It keeps the meat pink and protects it from bacteria. You can find it at specialty food stores or online.
If you don't have a smoker, you can cook the pork belly in a 200 degrees F oven until it registers 150 degrees F on a meat thermometer. (Times will vary; check after about 2 hours.)