Heat the oil in a large, heavy-based casserole dish over a low to medium heat. Cook the onion for 5 minutes until softened, then add the cumin, smoked paprika, cayenne pepper and crushed garlic and cook for another minute. Add the peppers and cook for a further 5 minutes until they begin to soften.
Add the chopped tomatoes, kidney beans, black beans and purée, and top up with water so the vegetables and beans are almost covered. Bring to a simmer and cook for 45 minutes until thickened. Just before serving, stir through the coconut and coriander.