You posted your image incorrectly.
It's not creating a .rar file, it's creating a .bin file. "bin" is a generic extension used for a lot of things, including CD images, which is why your computer tries to open it in 7-Zip. As shown at http://ximwix.net/mirrors/rhdn-old/index.php@topic=6763.0.html
, you can open this .bin file in YY-CHR or another tile editor (like Tile Molester).
If you haven't configured Windows Explorer to show extensions for known file types, you should probably do that – it will likely save you a lot of confusion if you keep working with things like this. (The precise way of doing so depends on your Windows version; Google will tell you more.)
Also, how can I decompress Super Mario World?
Were you unable to find the answer with a Google search..?