Is there some sort of way I can undo this paint job to the original aluminum look without having to repaint the wheels? Thanks

 

Do you have any idea what type of paint it is? Some of those wheel paints are peel-able, others would require solvent or stripping down to the metal. There's no way to tell what it will take to remove it unless you know what was done.

 

If they did the paint job properly, the original paint will be sanded to get proper adhesion with the new paint.
As DaleB said, some are actually peelable sprays - what does it feel like with your fingernail?
Does it feel like paint or a flexible coating?

 

Powder coating involves sandblasting the item down to its bare metal state and baking on a new finish using the powder coating color of your choice. If those wheels are powder coated, it isn't coming off unless you repeat the process. Because of the sand blasting prep, you can't really restore the original finish on those wheels, although you will discover, there are dozens of powder coating finishes to choose from.

​​​​​​​