Poach some of the salmon in milk and drain, reserving the milk. Make a white sauce using the poaching milk, it should be quite thick. Flake the salmon, add some sweetcorn and season and mix with the sauce. Leave to cool. Roll out some puff pastry (ready made is fine), cut into 4-6 inch squares. Place a dollop of salmon mixture into the middle, fold diagonally into triangles, seal the edges with beaten egg and glaze the top. Bake in a hot oven (gas 7, 220c) until pastry is cooked and golden. Serve hot, warm or cold, or freeze. Ideal for buffets, lunchboxes etc.
P.S. can use tinned salmon if not lucky enough to have a whole one in your freezer! Could also use this mix as a base for fish pie just put some mash on top and brown under the grill.