I don't think this trick has been mentioned before but here is the easiest way to right click on the screen.

All you need is Xbindkeys and Xmodmap.

This is what your /home/user/.xbindkeysrc script should simply look like:

"xmodmap -e "pointer = 3 2 1""
Return

"xmodmap -e "pointer = 1 2 3""
Return + Release

When you hold the Center D-Pad, or whatever key you decide, and tap on the screen, it will be a right click.

When you let go or anything else, it will always be a left click.