This is Rachael Ray's recipe and pretty much the salad I grew up on coming from an Italian family. The portions can be increased for larger groups. I love this simple and healthy salad. It is a perfect salad to serve with Italian food!
Place salad greens in a salad bowl and top with tomatoes, cucumbers, onion, and carrot. Place oil, vinegar and sugar in a small plastic container. Put the lid on the container and shake dressing until sugar dissolves, about 1 minute. Pour dressing over salad. Season salad with salt and pepper, to taste.