In a medium bowl, combine yogurt, mayonnaise, vinegar, and choice of herbs and spices. Whisk until smooth, allowing it to sit for 10 minutes.

Bring a large pot of salted water to a rolling boil. Add pasta and cook according to package instructions, about 8-10 minutes. Drain and rinse under cold water.

While pasta cools, slice cucumber into thin rounds or half-moons. Arrange on a kitchen towel to absorb excess moisture.

In a large mixing bowl, add cooled pasta, cucumber slices, and diced onion. Mix gently to combine.

Pour dressing over pasta mixture. Toss until well-coated, adjusting seasoning as necessary with herbs or spices.

Cover and refrigerate for at least 30 minutes to allow flavors to meld and chill before serving.