Like in Unity. As simply as that. =) Otherwise the left-hand-launcher (panel or whatever you would call it) would be quite useless to me.
You can do it through a AutoKey (get it from ppa). It allows You to bind any script to a hot key. Here's and example of script which You can bind to a hot key. It starts a
here's a script to bring LibreOffice window:
and so on!
As far as I know you can't, at least not yet. Here is the "Cheat sheet" for GNOME-Shell and at the bottom you find all the available keyboard shortcuts:
You can also look through the mappable keyboard shortcuts in the system settings and see a complete list there.