In a mixing bowl, combine olive oil, oregano, garlic powder, salt, and black pepper. Add the chicken breasts and marinate for at least 15 minutes.

Preheat the grill over medium-high heat. Grill the chicken for about 6-7 minutes on each side, or until fully cooked. Remove from grill and let rest before slicing.

While the chicken is grilling, prepare the vegetables by dicing the cucumber, halving the cherry tomatoes, and slicing the red onion and bell pepper.

In a small bowl, whisk together olive oil, red wine vinegar, dijon mustard, minced garlic, salt, and black pepper to make the dressing.

In serving bowls, layer cooked quinoa, grilled chicken slices, and the prepared vegetables.

Top with feta cheese, kalamata olives, and chopped parsley. Drizzle with the dressing before serving.