1. Put the pizza base on a baking sheet and spread the black olive paste to within 1 cm/1/2 inch of the edge.
2. Heat the oil in a frying pan (skillet) and cook the onion for 2 minutes. Add the garlic and cook for 1 minute.
3. Spread the onion mixture over the pizza base and arrange the tomato and chorizo slices on top.
4. Sprinkle with the oregano, season with black pepper and arrange the Mozzarella cheese and olives on top.
5. Bake in a preheated oven at 230C/450F/Gas Mark 8 for 10 minutes until the cheese is melted and golden. Serve immediately.