In a medium bowl, combine olive oil, dried oregano, garlic powder, paprika, salt, and pepper. Toss the chicken breasts in this marinade and refrigerate for at least 30 minutes.

Rinse quinoa under cold water. In a saucepan, combine quinoa and water or chicken broth. Bring to a boil, then reduce heat, cover, and simmer for 15 minutes.

Preheat a grill over medium-high heat. Cook marinated chicken for 6-7 minutes on each side until fully cooked, then let it rest before slicing.

In a large mixing bowl, combine cherry tomatoes, cucumber, red onion, Kalamata olives, parsley, and lemon juice. Toss to combine.

Assemble your bowls with quinoa at the bottom, followed by sliced chicken, salad mixture, and crumbled feta on top.

Serve with tzatziki sauce, if desired, and enjoy!