Don't worry, Jerry ;). Lots of people will understand it .... in the UK, at least.
'Hey presto!' is an exclamation taken from a magician's or conjurer's act. Just before the rabbit jumps out of the hat or the lady disappears in a puff of smoke, the magician says 'Hey presto!'.
You can say it to signal a sudden and surprising appearance, disappearance or sudden dramatic change.