Painting the rims of single speed bike
To do a proper job, get them blasted and powder coated.  This won't be quick or cheap.

First, price some brand new wheels as you want them to look.  This dollar-value is your hard upper limit, to compare with the costs of repainting.  No point spending more than this on your old wheels.


Disassemble wheel. You want bare naked rims with no spokes.  Store the loose parts safely.
Get it sand-blasted with glass or walnut or some other suitable abrasive.  This will clear the old coating off leaving bare metal.   Take the advise of your blasting company on the material.
Get it powder coated in bright orange or whatever colour you like.  Talk to the powder coating company about protecting the brake track if you intend to brake on it.  Otherwise powdercoat the whole thing.  This will take days to cure and harden.
Rebuild your wheels, true them, fit up and ride.


Other options might include getting your nipples and spokes powder coated too.  If you do this, buy some spares and get them coated at the same time, cos its not worth coating one spoke later.  Again, protect the threads from the coating.

Do please take before/after photographs and add them to an answer later.