If you are running Win98, you can operate
Genecyst to turn on/off the background or sprite layers, as well as give you the tilesets of the backgrounds, if you're masochistic enough to copy paste from scratch.
If you're running ME or XP Genecyst won't work, so get
Gens Plus. The only current Genesis emulator I know of that will allow you to add/remove sprite or background layers.
That's all I know. I assume that ZSNES will have the same functions, but I can't recall offhand.