Bring a pot of salted water to a boil and cook the whole grain pasta according to package directions until al dente.
Season the chicken breast with half of the garlic powder, sea salt, and black pepper.
Grill or pan-sear the chicken over medium heat for 6-7 minutes per side until fully cooked, then let it rest before slicing into bite-sized cubes.
In a small bowl, whisk together the Greek yogurt, olive oil, lemon juice, dried dill, and the remaining garlic powder, salt, and pepper to create the dressing.
Dice the cucumber, halve the cherry tomatoes, and finely mince the red onion.
In a large mixing bowl, combine the cooked pasta, cubed chicken, and chopped vegetables.
Pour the creamy lemon dressing over the salad and toss gently until everything is evenly coated.
Serve immediately or chill in the refrigerator for 30 minutes to allow the flavors to meld.