1) Heat the oil in a large saucepan over a medium heat, add the onion and saute until soft. 2) Add the peppers and garlic and saute for another 10 minutes or so. 3) Add the tins of tomatoes, water and chillies and bring to a simmer. 4) Add ⅔ of the chopped coriander and the mussels, place a lid on the pot and simmer for 5 minutes, or until all the mussels are open. 5) Serve in bowls with the rest of the coriander sprinkled on top and some chunky bread to mop up the sauce.