I've only seen it a couple of times but what is exactly involved when doing that.

I've see blue candy additive spray over a black carbon hood ( car was blue so they gave the hood a hue to match it ) .

 

Here's what I'm talking about if you can't picture it.

 

Should be as simple as wet sanding it with 600 and above till it's completely dull(being carefull not to go to far) then spraying your tint, then if you want to be **** wetsand the tint layer, then clear it and OFC wetsand and buff the clear as well!