For the Sous Vide Pork Belly
Season the pork belly with about half of the BBQ rub of your choice. Place the pork belly in the vacuum or Ziploc bag and seal. Sous vide the pork belly at 155°F (68.3°C) for 6 hours.
When complete, fire up your grill to 225°F (107°C) and use some pecan wood for smoke. Remove the pork belly from the bag and cube it up into 2-inch cubes. Place the cubes in a bowl and add the rest of the BBQ rub and toss to coat them completely. Place the cubes on a wire rack on top of a sheet pan (to catch the access fat) and place them in the grill for about 1 ½ hours.
Remove from the grill, discard the rendered fat, and toss the cubes in the bowl with the BBQ sauce of your choice. Place them back on the grill on the sheet pan for another 20-30 minutes to caramelize. They should be nice and caramelized, if not just cook them a little longer.
Remove from the grill and let rest for 10 minutes while you prepare the bread by adding the mayo and placing the lettuce and pickled onions on it. Add the pork belly and enjoy!