Drain cornhusks and open flat. Overlap wide, flat ends if 2 cornhusks to make a boat-shaped package. Repeat to make 8 packages. Divide onions among cornhusks and top each with shrimp and 2 tablespoons Charred Chile Salsa. Fold cornhusks edges firmly around filling and tie ends with kitchen string.
Place packages on grill.
To serve, open each plate. Garnish with avocado, cilantro and lime wedges. Serve with remaining salsa. Makes 4 servings. Charred Chile Salsa 1 ear corn, husked 1 red bell pepper 3 large ripe plum tomatoes 8 tomatillos, husked 4 garlic cloves, unpeeled small white onion, peeled 1-teaspoon olive oil 3 dried New Mexico chilies cup chopped fresh cilantro 1 tablespoons fresh lime juice 2 teaspoons brown sugar Salt and freshly ground black peppers to taste Prepare a grill.