Slice chicken thighs into 2-inch cubes, then place in an airtight container along with 8 ounces of the tzatziki sauce. Toss, then place in the fridge to marinate for 2 hours.
Using large, pre-soaked wooden skewers, add chicken pieces to 5 skewers.
In a large skillet over medium heat, add 3 skewers and allow to cook on both sides for 7 minutes.
Remove from pan and add remaining 2 skewers, again allow to cook on each side for 7 minutes.
In the meantime, assemble cucumber tomato salad by combining diced cucumber and tomato in a small bowl and tossing with olive oil and salt, stirring to combine.
Serve chicken skewer along with cucumber tomato salad, pita bread, and remaining tzatziki sauce for dipping.