In a large bowl, combine the cubed chicken, 1/4 cup olive oil, 3 tbsp lemon juice, 2 minced garlic cloves, dried oregano, 1 tsp salt, and 1/2 tsp black pepper. Toss to coat the chicken evenly. Marinate at room temperature for at least 15 minutes, or refrigerate for 30 minutes to 2 hours for deeper flavor.

Preheat your air fryer to 375°F (190°C). Arrange the marinated chicken in a single layer in the air fryer basket, ensuring not to overcrowd it (cook in batches if necessary). Cook for 12-15 minutes, shaking the basket halfway through, until the chicken is cooked through and lightly golden brown. (Alternatively, pan-fry over medium-high heat for 8-10 minutes, or bake at 400°F (200°C) for 18-22 minutes).

While the chicken marinates and cooks, prepare the tzatziki. In a medium bowl, combine the Greek yogurt, grated and squeezed cucumber, 1 minced garlic clove, chopped fresh dill, 1 tsp lemon juice, salt, and pepper. Stir well to combine. Taste and adjust seasoning as needed. Refrigerate until ready to serve.

In a saucepan, heat 1 tbsp olive oil over medium heat. Add the uncooked rice and stir for 1 minute until lightly toasted. Pour in 2 cups of water, bring to a boil, then reduce heat to low, cover, and simmer for 15-18 minutes, or until all water is absorbed and rice is tender. Fluff with a fork.

Divide the cooked rice among four serving bowls. Top each with a generous portion of cooked Greek chicken. Arrange diced cucumber, diced tomatoes, and thinly sliced red onion around the chicken. Garnish with Kalamata olives and crumbled feta cheese.

Spoon a dollop of fresh tzatziki sauce over each bowl. If desired, sprinkle with fresh chopped parsley or dill before serving.