There are quite a few GUI-based tools for modifying APKs built to run on Windows, but there seem to be significantly fewer available for Linux. However, we can add another to the list now, thanks to XDA Forum Member Slethen.
APK Suite is a Linux-based tool that allows you to manipulate APK files from a GUI instead of the traditional command line interface. It's currently in alpha stage, so some bugs are par for the course. However, it does offer the bare essentials you'll need to start fiddling with some APKs. Features currently include:
- Decomplile / Recompile
- MD5 Calculation
- Permissions Viewing
- APK Singing
Installation is pretty simple as explained by the developer himself:
"The reason the file size is so small is because it does not yet actually have the libraries downloaded, to do this simply:
Control Cenrtre => Download Required Files.
It needs to be ran as root for one time only to install aapt into the /bin/ dir. After that, root is no longer required.
You can also manually place aapt in /bin/ dir and chmod to 775 if you do not want to run the application as root."
If you think this might be of use to you, have a look at the original thread for more details.