Bring a large pan of salted water to the boil and cook the pasta until al dente.Meanwhile, start on the sauce.
Melt the butter in a frying pan and fry the garlic for a couple of minutes.
Add the cream, finely grated lemon zest, lemon juice and parmesan, pour in a little of the pasta cooking water too, season with freshly ground pepper and let the sauce simmer gently while the pasta finishes cooking.
Stir the chives into the sauce, then add the pasta and the salmon cubes. Toss well, and turn the heat up slightly if needed so the salmon gets a little more heat.
At the same time, adjust the consistency with pasta cooking water, and keep tossing until the sauce thickens and clings to the pasta.
Season to taste with salt and freshly ground pepper before serving, and top with a few extra chives, a little parmesan or more freshly ground pepper if you like.