Cook the orzo pasta according to package directions until al dente. Drain well and rinse immediately with cold water to stop the cooking process and prevent sticking. Set aside.

While the orzo cooks, prepare the vinaigrette. In a small bowl or jar, whisk together the olive oil, lemon juice, minced garlic, Dijon mustard, dried oregano, salt, and pepper until fully emulsified.

In a large mixing bowl, combine the cooled orzo, halved cherry tomatoes, diced cucumber, diced bell pepper, and finely chopped red onion.

Pour the lemon vinaigrette over the pasta and vegetable mixture. Toss gently until everything is evenly coated.

Gently fold in the crumbled feta cheese and chopped fresh parsley. Taste and adjust seasoning with additional salt, pepper, or lemon juice as needed.

For best flavor, cover the salad and chill in the refrigerator for at least 30 minutes before serving to allow the flavors to meld. Serve cold or at room temperature.