Cut the chicken into bite sized pieces if you are planning to grill it on skewers, or leave the chicken thighs whole, and place the chicken in a large zip top bag.
Combine the marinade ingredients in a small bowl or liquid measuring cup then pour it into the zip top bag with the chicken. Seal the bag, and work the marinade into the chicken. Let the chicken marinate for at least 30 minutes.
Thread the chicken chunks onto skewers if you have chosen to use them. Grill the chicken over medium to medium high heat, then slice the cooked chicken thighs into strips if you didn’t use skewers.
To serve, start with a piece of pita bread and spread it with a generous serving of tzatziki sauce. Pile on some chicken and chopped vegetables, and serve.