In a bowl, combine 1 tablespoon olive oil, 2 tablespoons lemon juice, 2 cloves minced garlic, oregano, salt, and pepper. Add chicken cubes and marinate for 15 minutes.
Combine quinoa and chicken broth in a pot. Bring to a boil, then cover and simmer on low for 15 minutes until liquid is absorbed. Fluff with a fork.
Heat a large skillet over medium-high heat with remaining olive oil. Add chicken and cook for 8-10 minutes until golden brown and internal temperature reaches 165°F.
In a small bowl, whisk together the Greek yogurt, remaining 1 tablespoon lemon juice, 2 cloves minced garlic, and fresh dill to create the sauce.
Toss the diced cucumber, tomatoes, red onion, and olives together in a separate bowl.
Assemble the bowls by layering 1/4 of the cooked quinoa, followed by grilled chicken, the vegetable mixture, and a sprinkle of feta cheese. Top with a dollop of the yogurt sauce before serving.