Here are the PowerShell commands to remove a feature.
Uninstall the feature.
Uninstall-SPSolution -identity “<WSP FileName>”
(For ex, Uninstall-SPSolution -identity “Deploy_Service_Requests_Lists.wsp”)
Remove the solution.
Remove-SPSolution -identity “<WSP FileName>”
(For ex, Remove-SPSolution -identity “Deploy_Service_Requests_Lists.wsp”)
* Note pay attention to SPSoluion (farm solution) vs SPUserSolution (sandboxed solution). You need what kind of solution you deployed to know which command to use.
Here is the link to install a feature.