How can i read cbr files?

Some time ago I am thinking about making an app to read cbr files. These files are like zip files that inside contain images of comics…

The only alternative to be able to read these files is to decompress them with the zip extension?

How can I remove the unzipped folders once the app is uninstalled?

CBR are RAR files. I cannot find a RAR extension. I would love to see if anyone has an unrar extension.