Preheat the oven at 200 degrees Celsius.
Cut the mozzarella cheese and the mushrooms in thin slices.
Spread the tomato sauce and the mushrooms evenly on the tortilla breads.
Place the ham slices on half of the tortilla breads.
Sprinkle the cheese and the mozzarella cheese on the breads.
Spread the oregano on top of the pizzas right before you place them in the middle of the oven for 10 minutes.
Take out the pizzas and serve them warm.
Spread the arugula on half of the pizzas.