Rinse the rice under cold water until the water runs clear. Combine the rice and 2 cups of water in a medium saucepan and bring to a boil over high heat.
Once boiling, reduce the heat to low, cover, and simmer for 15 minutes or until the water is absorbed and the rice is tender. Remove from heat and let it sit covered for 5 minutes, then fluff with a fork.
While the rice cooks, prepare the chicken marinade. In a medium bowl, combine 1 tablespoon olive oil, minced garlic, dried oregano, ground cumin, paprika, salt, and black pepper.
Add the chicken pieces to the marinade and toss to coat evenly. Let marinate for at least 10 minutes.
Heat the remaining 1 tablespoon olive oil in a large skillet over medium-high heat. Add the marinated chicken pieces and cook for 6-8 minutes, turning occasionally, until the chicken is cooked through and lightly browned.
In a small bowl, prepare the tzatziki sauce by mixing the Greek yogurt, lemon juice, fresh dill, garlic powder, salt, and black pepper. Stir until smooth and set aside.
Assemble the bowls by dividing the cooked rice evenly among four bowls.
Top each bowl with cooked chicken, diced cucumber, halved cherry tomatoes, chopped red onion, sliced Kalamata olives, and crumbled feta cheese.
Drizzle each bowl with the prepared tzatziki sauce.
Serve immediately and enjoy your Greek Chicken Rice Bowls!