In a mixing bowl, whisk together Greek yogurt, mustard, lemon juice, salt, and pepper until smooth and creamy. Let it rest for 10 minutes.

Bring a large pot of salted water to a boil. Add the pasta and cook until al dente, about 8-10 minutes. Drain and rinse under cold water.

Wash and slice the cucumbers, sprinkle with salt, and let drain in a colander for 30 minutes.

In a large mixing bowl, combine the cooled pasta, drained cucumbers, and chopped onions. Add any optional ingredients if desired.

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

Cover the salad and refrigerate for at least 30 minutes before serving.