If you can't find pork belly without the skin, it's very easy to trim off yourself. I place the pork belly skin side down on a cutting board. My other hand presses down on the meat to keep it flat, and with the knife hand cut off the skin by laying the knife flat 1/8" of an inch above the cutting board.
Apply the salt on all sides. Leave the meat in the fridge for a few hours, or even better, overnight.
Apply the rub on all sides, make sure you cover it evenly.
Wait for the grill to reach 140° C / 280° F.
Fire up the grill, prepare it for direct heat. I use one chimney full of briquettes here. Try to keep it at 140° C / 280° F. Place a few chunks of wood on the glowing embers for smoke flavor. Place the pork belly on the grates and close the lid. Smoke it for approximately 2 hours, it is done when the meat temp is 75° C / 167° F.
Place the pork belly in the middle, meat side down, and close the lid. Cook it for approximately 1 hour.
When it's been on for 1 hour, flip the meat so the fat side is down. Do a refill of briquettes if needed. I usually refill with half a chimney of briquettes at this time (which I light in the chimney before adding to the grill). Let it cook for another 40-60 minutes. Target temperature is 85° C / 185° F, then it's tender but still easy to slice.
Now bring the meat in, and let it rest for 15 minutes before slicing and serving. Enjoy a great tasting pork belly with an amazing flavor!