Step 1: Boil salted water and cook orzo until al dente (8–10 minutes). Drain and rinse under cool water.
Step 2: While the pasta cooks, chop cucumbers, tomatoes, onions, and herbs. Slice the olives.
Step 3: In a small bowl, whisk together olive oil, lemon juice, Dijon mustard, garlic, oregano, salt, and pepper.
Step 4: In a large bowl, combine the cooled orzo with the vegetables, herbs, feta, and olives.
Step 5: Pour the dressing over the mixture and toss gently until everything is coated.
Step 6: Chill briefly or serve immediately, garnished with extra feta or herbs if desired.