In a small bowl, combine Greek yogurt, lemon juice, Dijon mustard, honey, salt, and pepper. Whisk until smooth and let sit for 10 minutes.

Thinly slice the onion and soak in cold water for 10-15 minutes, then drain and pat dry.

Bring salted water to a boil, add pasta and cook al dente, about 8-10 minutes. Drain and rinse under cold water.

Slice the cucumber in half, scoop out seeds, and then slice it thinly.

In a large bowl, combine cooked pasta, drained onion, and cucumber slices. Pour dressing and toss.

Cover with plastic wrap and let rest for at least 40 minutes before serving.