Preheat oven to 220°C. Preheat two oven trays or pizza stones.
Pat chicken dry with paper towels and cut into 1cm strips. Place in a medium dish with spices and salt, mix well then marinate for 5 minutes while you prepare the rest of the meal. In a small bowl mix tomato paste with olive oil and set aside.
Heat a drizzle of oil in a medium fry-pan on a medium to high heat. Fry onion for 3 minutes until softened and golden. Remove from pan and set aside. Add a drizzle more oil to the pan and fry chicken for about 1 minute each side until golden (but not completely cooked through).
Lay 2 sheets of baking paper on the bench and place a pizza base on top of each. Divide tomato paste and oil mixture between bases and spread to cover. Sprinkle cheese evenly over bases, then top with onion, chicken, mango and capsicum.
Carefully lift up the baking paper with the pizzas on top and place on preheated trays then carefully slide baking paper away (use a fish slice to help with this). Cook pizzas until the bases are crisp and golden around the edges, 12-14 minutes. Swap position of trays halfway through cooking time so they cook evenly.
While pizza is cooking, mix all curry mayo ingredients together in a bowl and set aside.
To serve cut pizzas into wedges, place a few pieces onto plates with spinach leaves scattered over. Drizzle curry mayo over spinach and pizzas.