For the dressing: Put all the ingredients in a bowl and whisk together.
For the pita: Preheat the oven to 400 degrees F. Line baking sheets with aluminum foil.
Place the pitas on the prepared baking sheets. Brush each pita evenly with olive oil. Bake for 5 minutes. Top each evenly with fontina. Bake until the cheese is melted and the pita is lightly browned, 5 to 7 minutes.
In a medium bowl, toss the lettuce with Caesar dressing. Top each pita pizza with desired amount of salad, tomatoes, and chicken.