Preheat oven to 425 degrees. Coat 2 baking sheets with cooking spray.
Heat the oil in a large nonstick skillet over medium high. Add the onion and cook, stirring, 3 to 4 minutes, or until the onion is softened. Add the turkey and the taco seasoning mix and cook, stirring to break up the turkey into crumbles, for 5 to 7 minutes, or until it is browned. Stir in the tomatoes and cook another 5 to 6 minutes, or until the liquid has cooked down.
Meanwhile, coat a cast-iron skillet with cooking spray and cook the tortillas, 1 at a time, on both sides until crisp, about 2 minutes on each side. Transfer the crisped tortillas to the baking sheets.
Spoon the turkey mixture over the tortillas, spreading it evenly. Sprinkle the "pizzas" with the olives and the cheese and bake until the cheese is melted, about 6 to 7 minutes.