In a sealable container, combine boneless, skinless chicken breasts, olive oil, fresh lemon juice, red wine vinegar, Greek seasoning, and sea salt. Ensure the chicken is well-coated and marinate for at least 30 minutes at room temperature or refrigerate it overnight for optimal flavor.

While the chicken marinates, prepare the Tzatziki sauce by combining Greek yogurt, grated cucumber, minced garlic, lemon zest, additional lemon juice, fresh dill, and a pinch of salt and pepper in a mixing bowl. Stir until well mixed and refrigerate.

Heat a cast-iron skillet over medium-high heat for about 5 minutes. Place the marinated chicken in the skillet, cooking for approximately 3-4 minutes on each side until the chicken is browned and reaches an internal temperature of 165°F (74°C). Let it rest.

In a small bowl, whisk together olive oil, red wine vinegar, dried oregano, and a pinch of salt for the dressing.

Divide the cooked chicken among serving bowls. Top each portion with diced cucumber, halved cherry tomatoes, sliced red onion, and Kalamata olives. Sprinkle crumbled feta cheese and drizzle with the dressing.

Just before serving, add a generous dollop of chilled Tzatziki sauce on top of each bowl.