Preheat a pizza stone in the oven at 500F.
Remove the crust from the Italian bread and break the inside into small piece by hand and place in a bowl.
Add the tomatoes and mix well, with your hands preferably.
Add the cheeses, the onion, the oil, the oregano and the salt and mix well.
Take 1/4 of the dough, flatten it into a round shape, and spread some of the mix all over it.
Bake for about 15 mins on the hot pizza stone.