1. To grill the baguette slices: Preheat grill to medium-high heat. Place baguette slices directly on a grill and grill for 2-3 minutes, or until slices have grill marks. To toast the baguette slices in the oven: Preheat oven to 400 degrees F. Place baguette slices on a baking sheet. Bake for 7-10 minutes, or until baguette slices are golden brown and toasted.
2. To make the Greek Salad Bruschetta topping: In a medium bowl, diced tomatoes, cucumbers, kalamata olives, and red onion. Add red wine vinegar and feta cheese. Stir until well combined. Season with oregano, salt and pepper.
3. Top baguette slices with bruschetta topping. Serve immediately.