1. Wash and chop the romaine lettuce into bite-sized pieces. Place it in a large salad bowl.
2. Peel and dice the cucumber. Add it to the salad bowl.
3. Cut the tomatoes into wedges and add them to the bowl.
4. Thinly slice the red onion and add it to the salad.
5. Drain the kalamata olives and add them to the bowl.
6. Crumble the feta cheese over the salad.
7. In a small bowl, whisk together the olive oil, red wine vinegar, dried oregano, salt, and black pepper to make the dressing.
8. Drizzle the dressing over the salad and toss gently to combine.
9. Taste and adjust the seasoning if needed.
10. Serve the Greek salad immediately and enjoy!
Note: You can also add some grilled chicken or shrimp to make it a more substantial meal.