Preheat oven to 325°F. Arrange bread slices on a baking sheet. Brush olive oil over both sides of bread. Bake until golden, about 6 minutes per side. Remove toasts from oven. Rub cut sides of garlic over toasts.
Combine tomatoes and lemon juice in a medium bowl. Season with a generous amount of salt and pepper. Toss to combine. (Toasts and tomatoes can be prepared 1 hour ahead. Cover separately and keep at room temperature.)
Preheat oven to 350°F. Spread goat cheese over toasts; arrange on baking sheet. Mound tomatoes on toasts, dividing equally. Bake until heated through, about 8 minutes. Transfer bruschetta to a platter. Sprinkle with mint.