Preheat the oven to 450–500°F. Place a rack in the upper third of the oven. Prepare the homemade pizza dough of your choice.
Pour the canned tomatoes in a large bowl and crush them by hand. Season the tomatoes with the olive oil, oregano and a pinch of salt and pepper.
Spread the tomato sauce evenly over the pizza, leaving about 1 inch bare around the edges.
Drain the mozzarella from the water and gently pat dry with paper towels. Slice the mozzarella into 1-inch-thick slices and place them over the tomato sauce.