ZVS is a technique used in switching power supplies to reduce switching losses. The idea is that switching losses occur whenever there is overlap of voltage and current through the devices. Therefore, switching the device when either the voltage or the current is zero will reduce the loss.
Generally, that is accomplished with the use of resonant LC tanks (part of which parasitics can play a role- work with nature, not against it).
Sine tanks will produce a votage/ current swing, wait until the voltage/ current is zero, then switch the transistor.