The next day, drain the beans well, heat the olive oil in a large saucepan and fry the onion, garlic and cumin for 5 minutes until they start to colour. Add the beans and mix well. Pour over boiling water until the bean mixture is covered about 7cm (3ins), of liquid put on the lid and simmer for 2 hours. While the beans are cooking, mix together all the pico de gallo ingredients apart from the coriander. Add 1 tsp sea salt and mix well. Cover and leave at room temperature. When the beans are cooked and soft, drain well. In a very large frying pan, add the remaining oil and fry the onion, garlic, spring onion and spices until golden, then add the beans. Using a potato masher, partially mash the beans and mix well while cooking for 15 minutes. Meanwhile, make the guacamole. Roughly mash the avocados and lime in a bowl. Mix in the other ingredients and cover with cling film. Add the remaining coriander to the pico de gallo and grate the cheese. Microwave the tortillas for 10 seconds to soften. To serve, take one tortilla, top with beans, pico de gallo, guacamole, cheese and coriander and roll up the tortilla. Repeat until everything is used up.