Flotato apps are regular Mac apps. They just happen to be made from web apps, but your Mac doesn't care about that detail. So here's how to delete.
That's all there is to it.
Actually, no problem, either. Just create the app again and open it. Voila. All your settings are still there. If you want to destroy those settings, say, if you're giving away your Mac as a Christmas present, and you're too lazy to remove everything (not recommended) see the Advanced help section
on how to do just that.