In a bowl, mix together olive oil, garlic powder, dried oregano, cumin, salt, and pepper. Add the chicken breasts to the bowl and coat evenly in the marinade. Allow to marinate for at least 30 minutes or up to 2 hours in the refrigerator.
Preheat your grill or a skillet over medium-high heat. Cook the marinated chicken for 6-7 minutes on each side or until the internal temperature reaches 165°F (75°C). Remove from heat and allow to rest for a few minutes before slicing into strips.
While the chicken is resting, prepare the quinoa if not already cooked. Fluff it with a fork and set aside.
In a large bowl, combine the cooked quinoa, cherry tomatoes, cucumber, and red onion. Toss gently to mix.
To assemble the bowls, divide the quinoa salad among serving bowls. Top each bowl with sliced chicken, crumbled feta cheese, and a generous dollop of tzatziki sauce.
Garnish with fresh chopped parsley before serving.
Notes
Serve the bowls layered, showcasing the colorful veggies. Consider using deep bowls to allow each component to shine, and offer extra tzatziki on the side for dipping.