To delete your staging site using WPRemote:
Step 1: Go to the WPRemote website and sign up using your email ID.
Step 2: On the WPRemote site listing page, select the website of your choice.
Step 3: It'll take you to the Site Detail page. In the Staging Section, Click on the Arrow.
Step 4: Click on Delete Staging and it will ask to confirm your command. Click on Yes, Delete It and the staging site will be deleted.