To make the tomato sauce, combine all ingredients for the sauce in a saucepan. Bring to the boil over medium-high heat. Reduce heat and simmer for 15 minutes or until slightly thickened. Use a stick blender to purée to your desired consistency.
Place naan breads onto baking trays. Spread each bread with 11/2 tbs sauce and scatter with 11/2 tbs pizza cheese. Top with salami, olives, mushroom and capsicum. Scatter over remaining pizza cheese.
Bake for 10-12 minutes or until golden and bubbling, swapping trays halfway through cooking time. Slice pizzas in half and serve.