In a large pot, combine the water, the juice from the lemon halves, the shells, the boil, bay leaves, and 1 tablespoon of the salt. Bring to a boil, add the corn, and cook for 5 minutes. With a skimmer, remove the corn from the boiling liquid, put it in a shallow bowl, and let cool completely.
Meanwhile, bring the water back to a boil and add the shrimp. Cook for 5 minutes. Remove from the heat and drain. Remove the bay leaves, put the shrimp in a shallow bowl, and let cool completely.
In a small mixing bowl, combine the olive oil, mustard, lemon juice, hot sauce, the remaining 1/2 teaspoon salt, the black pepper, and garlic. Whisk to blend well.
In a large salad bowl, combine the corn, shrimp, basil, onion, tomatoes, and bell pepper. Add the dressing and toss to mix. Cover and chill for at least 2 hours before serving.
Yield: about 10 servings