Start by boiling a large pot of salted water. Cook the orzo until al dente, as per the package instructions. Once done, drain and rinse under cold water to stop the cooking process.
While the orzo is cooking, take this time to prepare the tomatoes, cucumbers, olives, and red onion.
In a large mixing bowl, combine the cooled orzo, halved tomatoes, chopped cucumbers, crumbled feta, halved olives, chopped red onion, and dried oregano. Drizzle with olive oil and 1 tablespoon of red wine vinegar. Toss the salad to mix well.
Taste the salad and adjust the flavors as needed. Add more red wine vinegar if desired, and season with salt and pepper to your liking. If you're using fresh parsley, sprinkle it on top as a garnish.