Island Shrimp and Pineapple Skewers with Rum Butter Sauce

Name: Island Shrimp and Pineapple Skewers with Rum Butter Sauce
Ingredients: 2 tablespoons fresh lime juice; 2 tablespoons olive oil; 2 teaspoons minced fresh ginger root, plus 2 teaspoons; 2 teaspoons minced garlic; 1 teaspoon red pepper flakes; 16 medium shrimp, shelled and deveined; 1/3 pound sliced prosciutto; 1 small pineapple, peeled, cored, and cut into 1-inch cubes; 2 tablespoons minced shallots; 1/2 cup dark rum; 6 ounces (1 1/2 sticks or 12 tablespoons) cold unsalted butter, cut into pieces; 1/4 teaspoon salt; 1/8 teaspoon cayenne; 1/2 cup minced fresh cilantro