Place the peppercorns on a double layer of cheesecloth. Gather edges of cheesecloth together, and tie securely. Combine cheesecloth bag, water, salt, red pepper, and lime quarters in a Dutch oven. Bring to a boil; cook 2 minutes. Add shrimp; cook 2 minutes or until done. Drain. Discard cheesecloth bag and lime quarters.
Combine shrimp, cilantro, lime juice, and jalapeño pepper, tossing well to coat. Heat tortillas according to package directions. Spoon 1/3 cup shrimp mixture into each tortilla; top each taco with 1 tablespoon tomato, 2 teaspoons sour cream, and 2 teaspoons onions.