Marinate Chicken: Cut chicken into strips (about the size of a chicken tender). Place in a medium-sized bowl and season with a little salt and pepper. Pour 1/4 cup of the Greek Vinaigrette over the chicken, toss to coat. Place in the refrigerator, covered, for 30 minutes. 

Make Tzatziki Sauce: Meanwhile, make the easy tzatziki sauce. Squeeze out as much water from the cucumber as possible. Add all ingredients to a food processor. Blend until consistency is smooth. Taste and adjust any seasoning, as-desired. Place in refrigerator, so that sauce can thicken. 

Prep Veggies: add cherry tomatoes, cucumbers and red onion to a small mixing bowl. Toss with the remaining tablespoon of Greek Vinaigrette. 

Cook Chicken: bring a large cast iron skillet to medium-high heat. Add a tablespoon of olive oil; swirl to coat the pan. In batches, cook chicken 2-3 minutes per side or until fully cooked (it is fully cooked when it reaches an internal temperature of 165 degrees F). Remove from pan and place on a plate. 

Make Gyros: take a piece of pita bread and place a couple pieces of butter lettuce on top. Add cooked chicken, tzatziki sauce, and the cucumber mixture. Enjoy!