Drain the beans into a sieve or colander, reserving the liquid and then run them under cold water for a couple of minutes.
Peel the onion and cut it into 8 wedges.
Cut the tomato into quarters.
Cut the stem off the jalapeno pepper.
Bash the garlic cloves with the side of a knife and then peel off the papery outer layer.
Heat the oil in a medium (20cm or 8") saucepan over a high heat and add the onion, tomato and jalapeno pepper and cook until they start to char and darken up, this will take around 8-10 minutes.
Add the garlic and cook for another minute or so, then remove from the heat.
Stir in the chipotle chilli paste, ground cumin and oregano until everything is coated, then transfer to a blender.
Add the black beans, including 175ml (¾ cup) of liquid from the tin, to the blender along with the cold water and blend until very smooth. You can also pulse this soup and leave it chunky if you prefer.
Return the soup to the pan, place on a low heat on the stovetop and simmer for 10 minutes.