Can't help you with sauces because I don't eat them.
But this works with any white fish:
Thinly slice some leeks and put them in a microwave dish, add seasoning and a splash of water, cover, and cook on high for 2-3 minutes. Then add your piece of fish, a squeeze of lemon or lime juice, cover again and microwave for another 2-4 minutes, depending on the thickness of the fish.
A thin fillet, like the tilapia I cooked this way the other day, will take just two minutes. A thicker piece will take longer. Do it two minutes at a time, to make sure you don't overcook it. (My microwave is 750 watts.)