Cook the pasta according to package directions until al dente. Drain immediately and rinse thoroughly with cold water to stop the cooking process and cool the pasta down. Set aside.

Prepare the vinaigrette: In a small bowl or jar, whisk together the olive oil, lemon juice, Dijon mustard, minced garlic, oregano, salt, and pepper until well emulsified.

If shrimp is not already cooked, quickly sauté or boil the shrimp until pink and opaque (about 2-3 minutes). If using pre-cooked shrimp, ensure it is chilled. Chop the large shrimp into bite-sized pieces.

In a large mixing bowl, combine the cooled pasta, cooked shrimp, halved cherry tomatoes, diced cucumber, chopped red onion, and fresh parsley.

Pour the zesty vinaigrette over the pasta mixture. Toss gently until all ingredients are evenly coated.

Taste and adjust seasoning if necessary (add more salt, pepper, or lemon juice for extra zest). Chill in the refrigerator for at least 30 minutes before serving to allow flavors to meld.