Since you're using Ubuntu, the OpenOffice cli command is indeed the one you indicated yourself; you just need to supply the exact path to a file. If you use the command without specifying a file name/path, it'll open a new text document.
I don't know a Ctrl+? shortcut to open a terminal, but apart from the solution BinJajer proposed, you can open a terminal and keep it open - you just need to send you processes to the background to keep it usable. In Ubuntu, you can also activate a GNOME taskbar applet called mini commander that gives you a limited cli to start programs from. A terminal to work in and mini commander to call stuff you'd just like to run turned out to be usable for me (I'm using this combination on my Debian system).
For YaKuake, do keep in mind that you'll need to install numerous packages if you're trying that on Ubuntu (in Debian, KDE's already there, but they don't have a YaKuake package for Sarge). 11 packages, 22 MB download, 75 MB disk space used - no small amount if you only use the libs for YaKuake.
btw. right click on your desktop - the topmost command to click is "open terminal"...