Take one Tuna Napolitana sauce sachet, and follow the destructions on it. However, instead of using a tin of tuna, add a tin of salmon. I used pink salmon when I made this up the other day (and because I'm lazy, I bought a tin of skinless & boneless). Simples!
Ideally you want some veg or something with it - I find it goes quite well with some rocket salad.
I get four servings out of this, which means one to eat now, one to go in the fridge for tomorrow (give it a couple of minutes in the microwave on high to reheat), and two to go in the freezer for whenever (I give it around 10 minutes on defrost stirring part-way through, then a couple on full blast to reheat it).