Well you are in luck. You can get mario kart on your droid but it will cost you. Here's what you need to do:
1. Download and install Snesoid from the market. This is the part that will cost you. It's worth the cash. It's definately worth the cash though. The free version won't let you use save states and possibly some other features.
2. ONLY DO THIS IF YOU OWN A COPY OF THE GAME YOU WANT TO PLAY. Ok with that disclaimer there, goto Roms4Droid and find a copy of mario kart there (this isn't exactly kosher if you don't own a copy of the original, but considering the snes is ancient technology I doubt anyone will be hunting you down).
3. Open Snesoid up and load whatever game you downloaded. If the game is in .zip format you don't need to extract it. Same thing if it's .smc format. If you get lost from this point I suggest reading up on other threads about how to use Snesoid. If you can't find the game you want from the site I provided, remember.that google is your best friend. Good luck
Edit: I posted a direct link to the site where you can find Mario Kart but edited it to just the name. The Snes is old technology so I doubt the mods here will care too much but just in case, ya know. Again, Google works wonders when looking for roms.