Preparation Prepare grill for cooking. Soak shrimp (still in shells) in salt water 5 minutes, then rinse well in a colander. Pound all chiles with garlic to a coarse paste with a mortar and pestle and stir in fish sauce and lime juice and sugar to taste. Transfer to a large bowl. Snip shells of shrimp with scissors down center of back, from wide end to second-to-last tail section. Butterfly shrimp in their shells, making a deep incision along length of back where shells are cut, and devein. Discard tough outer leaves of lemongrass and trim root ends. Thinly slice lower 6 inches of stalks. Grill shrimp on their sides on an oiled rack set 5 to 6 inches over glowing coals until shells are pink and slightly charred and shrimp are just cooked through, 3 to 4 minutes on each side. (Alternatively, grill shrimp in a hot well-seasoned ridged grill pan over moderate heat.) Toss shrimp (with shells still on) with chile mixture and stir in sliced lemongrass, shallots, scallions, and mint. Serve on a bed of lettuce and tomato with cilantro or mint.
Preparation Prepare grill for cooking. Soak shrimp (still in shells) in salt water 5 minutes, then rinse well in a colander. Pound all chiles with garlic to a coarse paste with a mortar and pestle and stir in fish sauce and lime juice and sugar to taste. Transfer to a large bowl. Snip shells of shrimp with scissors down center of back, from wide end to second-to-last tail section. Butterfly shrimp in their shells, making a deep incision along length of back where shells are cut, and devein. Discard tough outer leaves of lemongrass and trim root ends. Thinly slice lower 6 inches of stalks. Grill shrimp on their sides on an oiled rack set 5 to 6 inches over glowing coals until shells are pink and slightly charred and shrimp are just cooked through, 3 to 4 minutes on each side. (Alternatively, grill shrimp in a hot well-seasoned ridged grill pan over moderate heat.) Toss shrimp (with shells still on) with chile mixture and stir in sliced lemongrass, shallots, scallions, and mint. Serve on a bed of lettuce and tomato with cilantro or mint.