You will need:
tomatoes (cherry tomatoes are the most flavorful)
extra virgin olive oil
fresh garlic cloves
sea salt (course grind)
French bread (baguette) or baguette-shaped Italian bread
You can use any kind of tomatoes for this but I like to use the multicolored heirloom cherry tomatoes if I can find them. Yellow and orange tomatoes are usually slightly lower in acid content, so including at least a few of these with red tomatoes makes it especially yummy.
Chop or dice tomatoes into 1/4 inch pieces and place in a large bowl. Drizzle a few tbsp of extra virgin olive oil on top. Sprinkle with a good pinch of sea salt per tomato. Add a clove of garlic minced very fine. Chop a large handful of fresh basil finely and toss to mix.
NOTE: Although you can fry them in a skillet, I have had good luck recently with the following method of making the crostini:
Slice a baguette of good French/Italian bread into 1/2 inch slices. Slice on a slight diagonal for larger slices. Mix extra virgin olive oil and minced garlic and brush on both sides of each slice. Bake in a 300 degree oven until golden brown and crispy (1/2 to one hour) turn over midway through baking.
Spoon the tomato mixture onto cooled bread crisps and enjoy...