To make the red onion pickle, put the vinegar, sugar and salt in a small saucepan, cover with cold water and bring to the boil. Take the pan off the heat and add the onion. Leave to stand for 30–60 minutes. Drain well before serving.
To make the tortillas, place the flour and salt in a large bowl and gradually add the oil and 125ml/4fl oz water, stirring constantly until the mixture comes together to form a rough dough. Transfer to a lightly floured surface and knead for 5 minutes. Roll into a ball, wrap in cling film and chill for 30 minutes.
To make the beef taco filling, heat the oil in a large frying pan and cook the onion and peppers for 5 minutes, or until softened. Add the garlic and spices and cook for 1–2 minutes, stirring constantly. Add the mince and cook over a high heat for 2–3 minutes, or until browned, using a wooden spoon to break up any large chunks of meat. Pour over the stock, reduce the heat and simmer for 30 minutes, or until the mince is tender and the liquid almost evaporated, stirring occasionally.
Mix all the salsa ingredients together in a small bowl. Cover and keep chilled until ready to serve.
To make the black bean filling, mash the beans in large bowl with a potato masher, leaving some whole if you like. Heat the oil in a frying pan and fry the onion until softened. Add the garlic and cook for 1 minute. Sprinkle over the spices and cook with the onion and garlic for a minute before adding the mashed beans, lime juice, honey, salt and 250ml/9fl oz cold water. Bring to a simmer and cook for 3–4 minutes, or until the mixture is thick, stirring constantly. Add a little extra water if you prefer a looser texture. Adjust the seasoning to taste.
To finish the tortillas, divide the dough into eight pieces and roll into balls. Use a rolling pin to roll each ball on a lightly floured surface until it has a diameter of around 16cm/6¼in.
Place a frying pan over a high heat and when hot, cook the tortillas one at a time for 1–2 minutes on each side, or until lightly browned and cooked through. Dust off any excess flour from each tortilla before you cook it. Stack the tortillas on a plate and cover with a clean tea towel to keep warm.
Mix all the guacamole ingredients together in a small bowl.
Serve each tortilla with the spicy beef, refried beans, guacamole, salsa and quick red onion pickle on the side.