Put the shrimp in a large bowl of ice water. Add 1 tablespoon salt; stir to dissolve and set aside 20 minutes.
Meanwhile, heat 2 tablespoons butter in a large skillet over medium-high heat. Add the corn, 1/2 teaspoon minced garlic and all but a few tablespoons of the scallions; season with salt and pepper. Cook, stirring occasionally, until the corn starts browning, about 4 minutes. Add 3/4 cup water and the tomatoes. Bring to a simmer, then reduce the heat to medium low and cook until the corn is very tender, about 15 minutes.
Meanwhile, combine the Worcestershire sauce, lemon juice, hot sauce, rosemary and the remaining garlic in another large skillet over medium heat. Cook, stirring occasionally, until the liquid is reduced by half, about 5 minutes. Drain the shrimp, pat dry and add to the skillet. Add the remaining 4 tablespoons butter; swirl to melt. Cook, spooning the liquid over the shrimp, until cooked through, about 5 minutes. Serve the shrimp over the corn mixture; top with the reserved scallions. Serve with the bread and lemon wedges.