I think that you will find it will not work out. Without the fat there is no medium for the microwave to start exciting molecules and create heat. The same goes for trying to pop popcorn dry in a pot. It might pop but you will burn the heck out of it.
From a health perspective I would advise against using a microwave at all for any food. There is some suggestion that the widespread use of a microwave on food, in particular at fast food establishments, has some relation to the increase in colon cancer.
Please note that these are just my opinions based upon what I have read.
For popcorn I use my trusty $20 hot air popcorn Popper. My fiancé just loves popcorn with the movie. Sometimes I think she might have just agreed to marry me for my popcorn Popper. Or perhaps the automatic icemaker in the refrigerator. In any case...
Using a hot air Popper produces no fat. Unless you put something on it. It is quick to pop the kernels of the corn and there is no risk of bombarding the poor little molecules in a rather aggressive manner.
Actually, it is achievable as I have done it, using a brown paper snack bag and some string to tie the bag; HOWEVER, its not achievable in all ovens as its dependent on your particular ovens wattage. I wouldn't recommend using this method, though, as you have to be very careful about not burning it(for one thing). Another method that will serve your purpose(and avoid any safety issues) is to purchase a microwave popcorn popper. I found an inexpensive one at my Walmart. OR as Sean suggested, a hot air one. Either will serve the purpose on no oil.
You can make popcorn in most rectangular tupperwear that isn't too large or too high. What you do is you put water into the tupperwear, put the kernels in the tupperwear, not too much water but enough that it makes steam. Cover it, let a corner be open so that the top doesn't blow.
I can make popcorn in about 2 and a half minutes by doing this.
Don't put too much or the steam won't be able to pop the corn.