Begin by washing the potatoes, then place them in a saucepan (skins on), add salt and just cover with boiling water from the kettle. Put a lid on and boil for 10 minutes. Meanwhile chop the salmon into chunks and give it a few pulses in a food processor to chop it fairly finely (or you can do this by hand). Now place the salmon in a mixing bowl and add the capers, lime juice and chopped coriander leaves. Mix well and season with salt and cayenne.
When the potatoes have had their 10 minutes they won’t be cooked through, but that’s how we want them. Drain them and, when they’re cool enough to handle, peel off the skins and grate them using the coarse blade of a grater. Then carefully combine them with the salmon, trying not to break up the grated bits. Now take tablespoons of the mixture and slap them into cakes: you need to press the mixture firmly together but don’t worry about the ragged edges because these look pretty when they cook. Repeat until the mixture is used up: you should have 12 cakes.
Measure 1-2 tablespoons of oil into a frying pan and, when the oil is really hot, add the fish cakes. Fry them for 3 minutes on each side to a crusty golden colour. Drain on kitchen paper as they leave the pan and serve garnished with sprigs of coriander and accompanied by Toasted Sweetcorn Salsa.