Fitts' law talks about the time it takes to get from one item to another (gross simplification). Here is a reference: http://sixrevisions.com/usabilityaccessibility/improving-usability-with-fitts-law/
For testing the Kinect version versus the mouse, I would recommend developing a test plan that has a series of actions (click this button, then that button - basically, figure out how the application will typically be used) and then set up timings so that the time it takes between steps is monitored. Then use the mouse once and the Kinect once. You can figure out how much time it takes to navigate your application and test it that way. It won't show you how much movement is needed but it will show you how much it will impede you (if at all) to use the Kinect.
As for a software to do this for you, I do not know of any. I think this would be a custom test scenario. However, it shouldn't be hard to captue the timing of each click.