Marinated Cucumber, Onion and Tomatoes

3 medium cucumber, peeled and sliced 1/4 inch thick
1 medium onion sliced and separated into rings
3 medium tomatoes cut into wedges
1/2 cup vinegar
1/4 cup sugar
1 cup water
2 teaspoons salt
1 teaspoon fresh coarse ground black pepper
1/4 cu olive oil
Optional: basil leaves or fresh dill weed

Combine ingredients in a large bowl and mix well. 
 Refrigerate at least 2 hours.