In a small bowl, combine the first six ingredients. Pour half of the marinade into a large resealable plastic bag; add the shrimp. Seal bag and turn to coat; refrigerate for 2-3 hours, turning occasionally. Cover and refrigerate remaining marinade for basting.
Drain and discard marinade. Thread shrimp on metal or soaked wooden skewers. Grill, covered over medium heat or broil 3-4 in. from the heat for 2-3 minutes on each side or until shrimp turn pink, basting cooked sides of shrimp frequently with reserved marinade. Serve shrimp over lettuce or cucumbers and sprinkle with red pepper if desired.