Preheat oven to 220°C. Place 2 pizza trays in oven to preheat.
Place pizza bases on sheets of baking paper. Roughly mash tomatoes with a fork and stir in chilli sauce, if using. Spread sauce over bases. Place bases with baking paper on pizza trays and bake for 5 minutes.
Tear ham and place on pizzas. Toss broccolini with oil and arrange on pizzas with bocconcini, onion and parmesan. Bake for 12 minutes or until bases are crisp and cheese is bubbling. Slice and serve.