Starting in firmware revision 1.5.71 Leviton added a new, highly requested feature called Double Tap. Once your dimmer firmware has been updated you will gain the ability to double tap the top or bottom of the rocker. In both cases the dimmer will instantly jump to maximum on or off and ignore any preset on or off ramp rate settings. Note, you can click too quickly, the taps should be approximately a half second apart.
For information on how to update you firmware, please read "Checking and Updating Firmware on Decora Smart® Wi-Fi Devices"