Use a pair of kitchen shears or scissors to cut the backs of the shrimp and remove the vein. Set aside.
Combine the remaining ingredients except the barbecue sauce in a medium nonreactive bowl and stir well to combine. Add the shrimp and toss to coat evenly. Cover and refrigerate for at least 20 minutes, and up to 1 hour before proceeding.
Preheat a grill or grill pan to medium-high heat and spray with nonstick cooking spray. Once the grill is hot, remove the shrimp from the marinade and place on the grill. Cook for 4 to 5 minutes, then turn and brush generously with the barbecue sauce. Continue to cook on the second side for another 4 or 5 minutes, or until just cooked through, and brush with more sauce, on the other side, just before serving.
Yield: 4 to 6 appetizer servings