Yes do touch the throttle. In practise it is often only necessary to dip the throttle as Sammo says, as you get to the top of the wave and then power back on as you start down the other side. Its all about timing but even with practise you will get a few wrong. If the prop breaks the surface there is a good chance of it ventilating and loosing grip which normally requires the throttle to be closed before it will grip again.
Btw, cavitation is lots of little bubbles imploding (think of vacuum) around you prop which takes the nice paint job off and damages the surface. Ventilation is a pocket of air or exhaust gases enveloping your prop so there is no drive. There is a better description here which is worth a read.