Your image is infused into a hardened poly-resin surface. This means is it abrasion resistant and easy to clean. I like to use microfiber cloths for all artwork cleaning and care tasks. A damp cloth is the best option. You can use water, but if you have a stubborn, oily fingerprints, a normal glass cleaner will help with that. The stainless steel should be cleaned by applying your favorite polish to the microfiber cloth and then to the steel. This keeps the spray off you wall. Once applied turn the cloth over and gently buff the metal.
Now for the proper handling. I do not suggest installing your art in a moist area such as a bathroom without venting the humidity. Always store the art in a dry area and cover with a soft cloth to protect the stainless steel and art. And as with any artwork if damage does occur it is usually on a corner, so be careful when moving and installing this art.
This art is not protected by glass, but instead by an optically clear sheet of acrylic so normal ammonia-based cleaners are not a good idea. Repeated use of ammonia-based glass cleaners will eventually fog the acrylic. I recommend using plain warm soapy water on a damp microfiber cloth. Any non-abrasive dish soap without ammonia bleach will work fine. After soaping up the surface, rinse with a damp cloth then dry with a microfiber cloth before it air dries, this method will eliminate streaking. Another effective way to clean is with an LCD screen cleaner. Again, apply with a microfiber cloth and dry before it can air dry.
For proper storage and moving of this type of art I recommend always covering the surface with a soft cloth or foam packing sheets. This will prevent the surface from scratching. Acrylic is a soft surface and will scratch easier than glass. If you do happen to scratch the surface there are many compounds that can be used to buff the surface to eliminate surface scratches.
Cleaning of the stainless steel should also be done with a microfiber cloth. You can polish the steel with a household stainless steel polish. Apply to microfiber cloth then polish the steel with the grain in long stokes and finish the polish by going edge to edge with the cloth in one continuous motion.