Greek salads enjoyed by happy diners are usually reported to include romaine, iceberg lettuce, spinach, cucumbers, grape tomatoes, and Kalamata olives. The tomatoes, cucumbers, and olives are found in traditional Greek salads, but the addition of lettuce or spinach can depend on the chef. A maroulosalata salad includes cos (romaine) lettuce, as well as spring onions and dill. Some chefs also add red onions or red or green peppers. No Greek salad is complete without one very important ingredient: feta cheese.
The basics of your salad can be a matter of personal choice. Maybe you hate tomatoes or onions; that's okay. You can leave them out and build your salad the way you like it. The important thing is that you make sure the olives and feta cheese are in there.
If you want a bona fide traditional Greek salad—horiatiki—stick to just tomato, sliced cucumber, green pepper, sliced red onion, Kalamata olives, and feta cheese. You won't find anything else in your salad if you order one while dining in Greece.
Ideally, all your salad ingredients will be fresh as can be. If you use tomatoes, they should be nice and juicy. Cucumbers and other greens should be crisp.
Indeed, the simplest of all dressings on a traditional Greek salad is simply a drizzle of Greek extra virgin olive oil. Offer your guests a few wedges of lemon on the side so they can squeeze and add the juice to their own taste. You can also use just a little straight olive oil with a touch of water. A mixture of oil and vinegar goes well if you include cucumber in your salad.
For one cup of dressing that should cover all your salad choices— particularly maroulosalata—start with 3/4 cup Greek extra virgin olive oil. Add 1/4 cup good quality red wine vinegar, 1/2 teaspoon crushed Greek oregano, 1 teaspoon salt and a pinch of pepper. Whisk it all together, or pour the dressing into a jar, seal it tightly, and shake well to combine everything.
There you have it. Your dressing can be as much about your personal taste as the salad itself, but if you want to dine the way the Greeks do, you'll stick to olive oil and vinegar.