I've got a MHZ Gecko that I need a controller for. The motor that is in it is a 3200Kv walkera from ebay that will drive a 28mm carbon prop. What size brushless controller do I need?

I was looking at a 40A Jeti controller. Is that enough? Too much? Are there specific controllers for boats and cars versus airplanes, or can the controller I pictured below run my boat?

Not enough info out there for brushless beginners.