How do I remap my capslock key to be alt + tab. And shift + capslock to be shift + alt + tab?
use xsetkbmap or xmodmap
Here is a quick into I have written no avoid forgetting how I did it. I wont tell you how to map those specific keys, but you will be well on your way. There are links to more thorough documentation.
umm... the link: http://genja.org/wordpress/2010/10/setxkbmap-genja/
You need something like the contents of /usr/share/X11/xkb/symbols/compose: partial modifier_keys
.. just study the links I gave you and the world will be under your domination in no time!