Remove the pizza dough from the fridge and let it sit at room temperature for about 30 minutes. Arrange the oven rack to the lowest position and heat it to 500ºF.
Scatter the cornmeal over a large sheet pan. Stretch the pizza dough into a large roughly 16-inch circle and drape onto the pan. Working your way around the edge of the circle, lay the string cheese about 1-inch from the edge. Fold the edge over the string cheese and press to seal. Drizzle 1 tablespoon of oil over the crust and brush to coat. Scatter the crust with the sesame seeds and set aside.
In a small bowl, stir together the tomato passata, garlic, Italian seasoning, sugar, and remaining tablespoon of oil. Season with salt and pepper. Spread the sauce over the dough, avoiding the crust, and scatter with the shredded mozzarella cheese and pepperoni. Sprinkle over some oregano and red pepper flakes, if you’d like.
Bake the pizza on the bottom rack of the oven for 15 to 17 minutes or until the crust is golden brown.
Let the pizza rest for 5 minutes before cutting and serving.
