Have you got the "Tap trackpad with two fingers for secondary click" option turned on under Trackpad on the Keyboard and Mouse settings in System Preferences?
I wish you could just click on the very right of the touchpad for a right-click, but you can't.
Control+Click
or you can go into system preferences, keyboard and mouse, click on the trackpad tab, and under trackpad gestures, check "Place two fingers on trackpad and click button for right click" then you can do that. Or, after checking that box, check 'Clicking', then you just have to touch the trackpad with two buttons and 'ta-da' you've got right click