G'day, pettycache, and welcome to
Kunena.
The short answer is no. No I don't know how you can do that (show only the poll results to administrators and not to anyone else) but it should be too difficult to do if you are skilled with PHP or if you are willing to pay for someone else to make the necessary changes to customise your particular installation of
Kunena.
The ability to configure the poll feature - in the way that you mentioned - is not a standard facility of
Kunena. It's an interesting idea but I have my suspicions that it won't appeal to the majority of people. That doesn't mean that you can't do this.
Kunena is a free product but that doesn't mean that every request to adapt or customise its feature set to suit individual needs is done for free, either.
So, unless someone else has (or has had) a similar interest in tackling this issue, I think you'll have to wait patiently for the possibility that someone can explain what you need to do. On the other hand, if you would like to expedite matters, offering to pay someone for their time to assist you could be something you might consider.