From the documentation I can see that unique clicks are the number of unique visitors that clicked to a given domain ; for example, if the same visitor clicked 3 times on the same outlink, it will be reported as 3 clicks and 1 unique click.
My question is, is this tracked across sessions across time? For example, if a visitor enters on Monday and makes an outline, and then he enters next Monday again and does another outlink. Does unique click count as 1 or 2?
Both Mondays within the timeframe selected, of course