Brush both sides of bread slices lightly with olive oil.
To Bake: Preheat oven to 450 degrees. Place on baking sheet in the center rack of the oven. Bake for approximately 7 minutes or until lightly browned. Watch closely so that the crostini doesn't burn.
To Grill: Heat grill to medium-high. Grill 3 to 5 minutes on each side or until lightly browned with nice grill marks.
Top with desired toppings and serve immediately. The are best made fresh, but can be made a few days in advance and stored in an airtight container. The will get more crunchy as time goes by.