In a sealable container, combine the boneless chicken breast, olive oil, lemon juice, red wine vinegar, Greek seasoning, and sea salt. Seal and shake gently to coat. Let marinate for at least 30 minutes or overnight.

In a mixing bowl, combine Greek yogurt, grated cucumber, minced garlic, lemon zest, lemon juice, chopped dill, and a pinch of salt. Stir well, then cover and refrigerate.

Heat a cast-iron skillet over medium-high heat. Add marinated chicken and cook for 3-4 minutes on each side until golden-brown and internal temperature reaches 165°F (74°C).

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

Slice the cooked chicken and divide among bowls. Top with cucumber, cherry tomatoes, red onion, Kalamata olives, and crumbled feta. Drizzle with dressing and tzatziki.