Place bread cubes on a jelly-roll pan. Bake at 375° for 20 minutes or until crisp and golden brown, turning cubes once.
Combine tomatoes and 1/4 teaspoon salt in a large bowl. Sprinkle shrimp with remaining 1/4 teaspoon salt and black pepper. Heat olive oil, red pepper, and garlic in a large nonstick skillet over low heat; cook 5 minutes or until warm and fragrant. Increase heat to medium-high. Add shrimp to pan; sauté 2 minutes or until shrimp are done, stirring frequently. Stir in lemon juice. Add bread, shrimp mixture, and basil to tomatoes; toss gently to coat. Let stand 5 minutes before serving.