If your Kixie dialer is taking up the full screen...
Drag your cursor to the top of your screen to access your Chrome browser menu (File, Edit, View, History, etc.), then you should be able to click "View" and then "Exit Full Screen".
In the future, instead of maximizing Kixie, just click and drag it from the corners to make it larger or smaller.
If the font size of the dialer is too large and you can't access all of the different tabs...
You can zoom in and out within the PowerCall, to make the text larger or smaller.
If you want to get Kixie out of your way, feel free to minimize it, but do not close out of it, otherwise you will not be able to receive incoming calls.