you need a remote with a relay on the receiver to be able to turn it off remotely.
Such as the maytech remote https://maytech.cn/products/maytech-new-waterproof-remote-control-mtskr1905wf-for-esk8-esurf-with-display-and-wireless-charging-functions
or a mini remote https://diyelectricskateboard.com/collections/remote-controller/products/torqueboards-2-4ghz-mini-remote-controller
(this is ugly but can be modded as such The Avio Mini Remote Mod) it’s a great remote, @b264 is in a very deep relationship with his. 
otherwise you can use a buck converter which will bring down the voltage of your battery pack to a selected voltage (5v-12v-14 etc…) and have a power button on the board to to turn it off and on.
Or use a 5v led strip and a portable powerbank with velcro and power it that way.