is it possible on a mac to quicky see the desktop along with the last active window? Many times, I feel the need to keep the current window open while having access to the desktop.

A good scenario to picture where this could be handy is this:

Say, you are on a web page and you want to drag a picture to desktop. If you are seeing a piece of the desktop at that moment, then no problems, just drag the pic to that spot but, many times, it turns out that the entire desktop is covered by underlying other windows. Sure, there is a hot-corner trick you can apply that will get you the desktop, but that action will also take down the current window, the one you wanted to drag the picture from. 

As far as I know, there is no way around this problem. 
So I end up minimizing the underlying windows to get a piece of the desktop to drag picture onto.

But I'll ask it anyway... 
Is there a way that would do what I'd like to do?
Simplest is in the Dock - 

Hold  Alt ⌥  &amp; Right Click > Hide Others



Alternatively &amp; probably better than my original answer [I don't know if this is system-wide, but it does appear in all the apps I checked, Apple &amp; 3rd party]
 Cmd ⌘   Opt ⌥   H  is the key command to Hide Others