Heat olive oil in a large skillet over medium high heat. Working in batches, add zucchini and cook, flipping once, until golden, about 1-2 minutes on each side; season with salt and pepper, to taste.
Place zucchini rounds onto a large baking sheet. Top each zucchini round with tomato sauce, mozzarella and pepperoni minis.
Place into oven and cook until the cheese has melted, about 1-2 minutes.
Serve immediately, sprinkled with Italian seasoning, if desired.