What brushless motor do I need for a 90kg electric longboard at 32km/h?

[Milkman64]

What type of brushless motor (watts, and kv) would I need to move 90kg of total weight (including longboard, battery, electronics and person) 32 km/h using a direct drive system from motor to wheel?
Similar to this:www.kickstarter.com/projects/424686603/kickr-electrify-every-longboard

 

[Khashishi]

Obviously it takes more power to go uphill or through rough terrain. On smooth terrain, I guess 250 watts or so. It's not going to be exact. Check out this:
http://www.kreuzotter.de/english/espeed.htm