Spread each flour tortilla with about a tablespoon of refried beans. Place a hard taco shell on one side of the tortilla, and gently fold the other side over to encase the shell. Press gently so you don’t crack the shell (though it’s not the end of the world if you do!).
Place the 6 double decker taco shells in a baking dish, open side pointing upwards. Set aside.
Preheat the oven to 190°C (Gas Mark 5 / 375°F).
Heat the oil in a frying pan, and add the onion, garlic, chickpeas and spices. Cook over a medium-low heat for 5-10 minutes, until the vegetables are soft. If you want, you can turn the heat up a touch to get a little bit of char on the vegetables.
Add the halved tomatoes, and cook for another few minutes, until the tomatoes have cooked down. Squash the tomatoes with a wooden spoon to help speed along the process. Alternatively, you could use a couple of tablespoons of salsa to save time.
Distribute the chickpea mixture evenly into the 6 taco shells, and top each with some grated cheese. Bake for 15 minutes, until the cheese has melted.
Add your chosen cold toppings to each taco, and serve immediately.