Boil the pasta in salted water until al dente. Drain and immediately rinse under cold running water until the pasta is completely chilled. Shake well to remove excess moisture.
In a large bowl, whisk together the Greek yogurt, mayonnaise, lemon zest, lemon juice, minced garlic, salt, and pepper until smooth.
Add the cooled pasta to the bowl with the dressing. Toss until every piece is well-coated.
Gently fold in the cucumber half-moons, shaved red onion, and fresh dill. Using a light hand keeps the cucumbers crisp and prevents them from bruising.
Cover and refrigerate for at least 30 minutes before serving. This allows the flavors to meld and the pasta to absorb just a bit of that zesty lemon-garlic dressing.
