Basically you're using the critical health version of the character's "Power Blow" (hey I don't name 'em) to knock your opponent into environmental hazards specific to the stage. On The Show, I did this in Versus with the AI cranked down, and picked Kasumi. Let the AI knock your health down until your health bar is blinking red, then sidestep and lead the AI into being between you and the giant clown head. Hold away + LB (default controls), and if successful you should have a cutscene for the attack, and the clown's mouth suddenly glowing orange.
Not sure if the other objects can be used, but that's how it popped for me below...
[edit: 20160803]
MS deleted video, xboxdvr.com cached it hoorj