Bring a large pot of salted water to the boil. Add a tablespoon of olive oil and the pasta and cook according to the instructions on the pack. When it is cooked, drain it and set aside. Keep warm.
Meanwhile, heat the rest of the oil in a wide pan and add the scallions and chilis. Cook very gently until the scallions are soft.
Put the tomatoes in a bowl and cover with boiling water. Leave for 1 minute then drain and cover with cold water. If you then slit the skins with a sharp knife they should peel off easily. Quarter the peeled tomatoes and remove any tough stems.
When the leeks are soft, add the tomatoes, salmon dice, frozen shrimp and the coconut milk. Bring back to the simmer and cook gently for 3-4 minutes or until the salmon is cooked and the prawns defrosted and heated through.
Turn on the broiler. Season the fish to taste with sea salt, black pepper and lemon juice - make sure it is well seasoned as the flavour will be ‘diluted' by the pasta - and then mix it gently into the pasta.
Turn the fish and pasta into a casserole or pie dish and sprinkle over the breadcrumbs.
Toast under a hot broiler until the crumbs are crisp then served at once with a green salad.