I forgot we were out of olives when I made this, so this photo is not fully representative of the salad. But you can use your imagination. You don't have to serve it on lettuce, but that helps stretch it out a little further.
adapted from Allrecipes.com
3 Roma (plum) tomatoes, seeded and chopped
1 large cucumber, peeled and chopped
1/2 cup thinly sliced onion (or red onion)
1/2 cup pitted kalamata or black olives
1/4 cup crumbled feta cheese
1 (10 oz) package Romaine salad, optional
1/4 cup olive oil
1 Tbsp. red wine vinegar
1 Tbsp. lemon juice
1/2 tsp. dried oregano
1 garlic clove, minced
salt & pepper to taste
Combine dressing ingredients in a small bowl or container and let stand 1 hour.
In a medium bowl, combine tomatoes, cucumbers, onion, and olives (if using). Pour dressing over and stir to coat.
In a large, shallow salad bowl, spread Romaine evenly in bottom. Top with tomato mixture. Sprinkle with feta cheese. (Or you can just toss it all together in a large bowl.)