In a mixing bowl, whisk together olive oil, 2.5 tablespoons of lemon juice, minced garlic, oregano, paprika, salt, black pepper, and red pepper flakes until well combined. Add the chicken breast chunks, ensuring they are fully coated in the marinade. Cover the bowl and allow the chicken to marinate in the refrigerator for at least 15 minutes, ideally 30–45 minutes.

While the chicken marinates, chop cucumbers, tomatoes, bell pepper, red onion, and parsley into uniform pieces. In a separate bowl, gently combine these diced ingredients and crumble in the feta cheese. Dress the mixture with the remaining 1 tablespoon of lemon juice, and season with salt and pepper. Give it a good mix and let it sit for a few minutes.

Heat a skillet over medium-high heat. Once hot, add the marinated chicken chunks in a single layer. Cook for 3-5 minutes on each side or until the chicken reaches an internal temperature of 165°F.

Warm the pitas by heating them over a gas flame or in a dry skillet for about 1-2 minutes per side, or by wrapping them in foil and using the oven at 350°F for about 5 minutes.

Take a warmed pita and fill it generously with the golden chicken pieces. Add a spoonful of the fresh salsa on top, and finish with a drizzle of tzatziki sauce.