In a mixing bowl, combine the sliced chicken breast with olive oil, dried oregano, garlic powder, onion powder, paprika, salt, and pepper. Stir until all the chicken pieces are well coated. Allow the chicken to marinate for approximately 30 minutes at room temperature, or for optimal flavor, refrigerate for up to overnight.
While the chicken is marinating, make the tzatziki sauce. First, drain the grated cucumber by placing it into a clean cloth or using a paper towel to squeeze out excess moisture. In a medium bowl, combine the Greek yogurt, drained cucumber, minced garlic, chopped dill, lemon juice, and salt. Mix thoroughly, taste, and adjust the seasoning if necessary. Refrigerate until ready to serve for the best flavor.
Heat a skillet over medium-high heat. Add the marinated chicken strips to the skillet and cook for 6-8 minutes, stirring occasionally. Ensure the chicken is cooked through and lightly browned for a delicious texture.
During the last few minutes of cooking the chicken, warm the pita bread. This can be done by adding them to another skillet over low heat or placing them in the oven for about 5 minutes until they are soft and heated through.
To assemble, take a warm pita bread and lay a generous handful of fresh lettuce or arugula on top. Add a portion of the cooked chicken strips, followed by a few slices of fresh tomato and red onion. Finish with a generous drizzle of tzatziki sauce over the filling.
Wrap or fold the pita around the filled ingredients for easy handling. Serve immediately, accompanied by additional tzatziki on the side for extra dipping pleasure.
Notes
Arrange the gyros on a rustic wooden board lined with parchment paper for presentation.