1/4 cup plus 2 tablespoons olive oil, preferably extra-virgin
2 tablespoons red wine vinegar
2 cloves garlic, crushed lightly with the side of a knife blade and minced
1 white onion, cut julienne
1 large cucumber, peeled, seeds removed and thinly sliced
1 1/2 pounds ripe tomatoes, cut into wedges
Salt and freshly ground black pepper