Bring a large pot of salted water to a rolling boil. Add the pasta and cook for 8–10 minutes until al dente. Drain and rinse under cool water.

In a large mixing bowl, combine the cooled pasta with chopped cucumber, celery, red bell pepper, cooked peas, and tuna. Gently fold to mix.

In a medium bowl, whisk together yogurt, mayonnaise, lemon juice, mustard, dill, garlic powder, salt, and pepper until smooth.

Pour the dressing over the salad mixture and gently stir until everything is coated. Adjust seasoning as needed.

Cover and chill in the refrigerator for 20-30 minutes before serving.