What do you think can we reduce to minimalistic powertrain, standing on the battery platform, nothing else?
Here is the inspiration…
minima foil
https://www.instagram.com/p/CK0za_aiynb/?igshid=13kf7uwhnwds7
Even with all the power in the world and/or starting from boats and docks you are going to want enough volume for floatation. The motor and battery are heavy enough to sink some thinner boards.
Yeah need to get some light carbon foil mast set. I thought I saw someone had one that could float… although not with a motor on there I’m sure.
That and and 80100 motor (would probably be lighter then a flipsky motor), 20-30 minute battery pack. You probably could calculate what volume board you’d need to keep the thing floating and go from there.
Or leash it to your foot and wear a lifejacket 
There’s already another whole thread debating this. #searchisyourfriend
Among others things, this is one of the reasons why Supernova failed. If you’re using a belly button take-off method to minimise the drag, you need a minimum surface/volume to glide that will lift your hips above the water. To minimize the board volume above the hydrofoil, we could imagine a small body board stuck on your chest plus a take-off technique that remains to be invented in a barefoot style.
If I sum up the all-up weight will be approx. 20kg… So 30l Volume platform with straps should do it? 
Yep , need to consider the volume of the wing , some wing are positive
Volume and maybe minimal area , after that everything is possible :
The Slingshot 84 is all wood inside and has a lot of flotation. How would you manage to stand up? Maybe towed by a boat for a wakeboard style start and then hit the switch and drop the rope. Use the Manta inflatable set up, with an inner tube around it. That would work to figure it out.