I love the look of glass tile with granite countertops, if you never got around to doing your backsplash you can try and get samples from somewhere online. I think glass tile is way easier to clean and if you go with a tile like stacked subway your area will look much more streamline. Subway...
That rust appears to be quite deep anyway and attempted removal may break, chip or peel the metal. If it were simply surface rust you could apply a little bit of steel wool and soapy water, but in this case leave it alone and enjoy it for what it is; can you really imagine that box having such...