Step 1. Prep.
Thoroughly clean the rims with a degreaser.
Wet sand the chrome and rinse. Allow to dry.
Mask off the rim using playing cards. (Much better than masking tape). They create a very precise mask and it only takes about 5 minutes.
Step 2. Prep some more.
Flip over the wheel and place on a bucket. Use another deck of cards to mask off the other side of the rim to prevent overspray onto the tire.
Step 3. Primer.
Use a self-etching primer. I used Duplicolor - available at auto parts shops. Let dry, lightly sand, add another coat of primer.
Step 4. Paint.
Use Appliance Epoxy paint by Rust-oleum. I recommend painting one side and flipping it over to paint the other side before the first side dries. To keep from marring the wet paint, I propped the rim up on a small bowl, on top of the bucket. The small bowl fits inside the area I'm not painting.
Step 5. Mount Wheels and Ride.