Cook the spaghetti al dente in salted water according to the instructions on the packet.
Meanwhile, drizzle the cubes of salmon with lemon juice. Add lemon zest, pepper and salt. Then fry in 1 tablespoon oil with the spring onions in a non-stick pan for about 5 minutes.
Deglaze the whole thing with the white wine and let it reduce briefly. Add the cream and stock and bring to the boil briefly. Season to taste with pepper, salt and sugar. Then add the wild garlic and tomatoes and simmer for about 5 more minutes.
Arrange the spaghetti on plates and pour the salmon and wild garlic sauce over the pasta.