First you need to download the "RT Jailbreak tool by Netham45" to unlock the signature verification of Windows RT and allow it to run unsigned ARM applications:
Follow the instructions in the readme.txt
Usage 1. Boot your RT device and log in, allow it to sit on the desktop for about a minute. 2. Extract all files out of the latest version of the .ZIP attached to this post. To do this on Windows RT, right-click on the .zip, choose 'Extract all', and select the destination folder. 3. Run runExploit.bat. It'll prompt you to either install the jailbreak to run on login, uninstall it not to, or run the jailbreak once. 4. Choose an option and follow all subsequent prompts. They're all quite easy and self-explanatory
Or visit the forum xda-developers for more info:
Then download the binaries of 7-zip ARM version from here: http://file.wizrd.tk/7ZARM.zip
Run 7zFM.exe and voila! extract and compress .zip, .rar, .7z, etc. on Windows RT for free!
Thanks for watching n have a nice day