In a medium saucepan, combine the rinsed quinoa and water. Bring to a boil over medium-high heat.
Once boiling, reduce heat to low, cover, and simmer for 15 minutes or until the quinoa is tender and water is absorbed.
Remove from heat and let the quinoa sit covered for 5 minutes, then fluff with a fork.
While the quinoa cooks, preheat a grill pan or skillet over medium-high heat.
In a small bowl, mix olive oil, dried oregano, garlic powder, salt, and black pepper.
Brush the chicken breasts with the olive oil mixture on both sides.
Grill the chicken breasts for 6-7 minutes per side or until the internal temperature reaches 165°F (75°C) and the chicken is cooked through.
Remove the chicken from heat and let it rest for 5 minutes before slicing into strips.
In a small bowl, combine Greek yogurt, lemon juice, fresh dill, minced garlic, salt, and black pepper. Stir well to make the tzatziki sauce.
To assemble each bowl, divide the cooked quinoa evenly among four bowls.
Top each bowl with sliced grilled chicken, cherry tomatoes, diced cucumber, sliced red onion, kalamata olives, and crumbled feta cheese.
Drizzle each bowl with tzatziki sauce and garnish with chopped fresh parsley.
Serve immediately and enjoy your high protein chicken Greek bowl.