1. Use a paring knife to cut along back of each shrimp shell, leaving shell on head intact; remove vein. Transfer shrimp to a shallow nonreactive dish. In a small bowl, stir to combine lemongrass, chiles, coriander, garlic, lime, and oil; pour marinade over shrimp. Cover; refrigerate overnight.

2. Heat grill to medium-high. (If using charcoal grill, coals are ready when you can hold your hand 5 inches about grates for just 3 to 4 seconds.) Remove shrimp from marinade, wiping off excess, and season with salt and pepper. Skewer shrimp from head to tail and grill until shell is slightly charred and shrimp are cooked through, 3 to 4 minutes per side. Serve hot with a squeeze of fresh lime juice.