Am I cooking frozen fish safely? I am always ultra paranoid about cooking food properly - especially fish.

I have started buying frozen salmon. On the packet it says to cook from frozen covered with some water in the microwave. I wanted to make some salmon pasta so I prepared a white sauce (with onion,garlic,flower,water,button,milk,wine,herbs,etc), half cooked the salmon in the microwave then cut off the silver bit, cut it into chunks and chucked the chunks into the sauce to cook for a while.

Is this ok or should I make sure the salmon is completely cooked before adding it to the sauce?
Freezing kills the parasites in fish that are harmfully to humans.  That is why all sushi fish has to be frozen before use.  Since the salmon is frozen and has spent way longer than the minimum time frozen you could consume the fish raw with no danger to yourself.  You could have added the fish frozen to your sauce if you had wanted.  

That said, I almost always thaw frozen fish at low power in the microwave so that it is easier to work with.