In a bowl, mix olive oil, garlic powder, oregano, lemon zest, salt, and pepper. Add the chicken breasts, ensuring they're well-coated. Cover and let marinate in the refrigerator for at least 30 minutes.
If not already prepared, cook quinoa according to package instructions. Set aside to cool.
Preheat a grill or grill pan over medium-high heat. Remove chicken from marinade and grill for about 6-7 minutes on each side, or until fully cooked and the juices run clear. Let the chicken rest for 5 minutes before slicing.
In a large bowl, combine diced cucumber, cherry tomatoes, sliced red onion, Kalamata olives, and chopped parsley. Drizzle with lemon juice and toss gently to mix.
In each serving bowl, layer a scoop of quinoa as the base. Top with sliced grilled chicken and the vegetable mixture.
Sprinkle crumbled feta cheese over the top and place a generous dollop of tzatziki sauce on the side or on top.
Enjoy your Greek chicken bowls while they're fresh!
Notes
Serve the bowls with lemon wedges on the side for an extra burst of flavor and freshness. Consider using a colorful bowl to enhance the vibrant colors of the dish.