Right click shortcut for Mac Lion OS?

Finally I got my answer:

Go to System Preference --> Universal Access --> Mouse --> Enable Mouse Keys (ON)

This will Enable you Numpad keys. Press Ctrl + 5 for Right Click.

Solution in MacOS Catalina - With every release, Apple is organizing all accessibility related controls under Accessibility in System Preferences. Steps to enable context menu (right click) with keyboard-

1. System Preferences --> Accessibility
2. Accessibility --> Pointer Control
3. Alternate Control Methods --> Enable alternate pointer control options
4. Select this checkbox to enable this option
5. Click on the options button next to this option --> Default for right click is F12

Fn-Ctrl-I on laptop

thanks to this post: https://discussions.apple.com/thread/2018015?start=0&tstart=0