Nevermind, Ive answered my own question, and here it is for all of you who might have the same problems:
you can access all files to steam and tf2 here:
/home/YOUR USER NAME/.cxoffice/win2000/drive_c/Program Files/Steam
(put a decal somewhere in here to use a custom decal)
To start the game at any resolution that you would like, you can specify it in the launch options
(in steam right click the game and go to properties, then "set launch options") here is what mine looks like:
-gl -console -novid -heapsize 512 -width 1640 -height 1000 -windowed
note
-novid sets it so that it wont play the opening video when you launch the game, -heapsize 512 sets the default ram higher for the game to run quicker. (only use it if you have a lot of ram, i have 2gigs).
since its windowed, there is no need to mess with twinview. should you want to run at full screen, you will have to disable twinview on the monitor you dont want to display the game, in the terminal enter:
sudo nvidia-settings
and disable it there.