Remove the silver skin from the ribs. Scrape any excess fat off both sides of the meat with a table spoon and cut any excess fat off with kitchen shears. Place the ribs on a large baking sheet.
Rub 1 tablespoon mustard onto one side of the ribs. Sprinkle about 1/2 cup of the rub over the mustard and gently pat the rub over the entire surface of the ribs so it adheres well. Flip the rack over and repeat on the other side. Repeat with the other rack of ribs. Cover with foil and refrigerate for at least 2 hours but up to a day or so ahead.
Prepare your grill or smoker with charcoal and bring the temperate up to 250°. Add the hickory chunks to the coals. Place a disposable roasting pan or metal bowl filled with water above the coals and place the grilling grate above the water.
Place the ribs on the rack above the water pan, bone side down. Close the lid and maintain the grill/smoker temperature of about 250°.
Smoke the ribs for about 3 hours or until the internal temperature is about 145-150°. Wrap the ribs loosely in heavy duty aluminum foil and return to the grill for another hour.
Meanwhile, pour the bottle of barbecue sauce into a medium saucepan. Add lime juice and zest, sesame oil, sriracha and Worcestershire sauce. Bring to a simmer and cook for about 15 minutes. Keep warm while ribs are finishing.
Remove the foil wrapped ribs from the grill. Carefully remove the water pan from under the grill grate and let the coals get a little hotter.
Unwrap the ribs from the foil and place back on the grill grate directly over the hot coals, meat side down. Cook for 15-30 minutes, being careful not to let the ribs burn.
Remove the ribs from the grill. Cut into 1-2 rib sections and serve with barbecue sauce.