What is the quickest way to deselect features that are highlighted as report results?

Once you have run a report, and have some features highlighted on the screen in yellow, your map might look something like this:

If you click on the Maps icon in the Navigation control, you will be able to see the highlighted selection in the legend:

To turn off the selection, click the green dot to the left of the entry. To remove the selection from the map, close the report. 

That's it!