To delete a recording of a Zoom session, sign in to the Zoom website at http://strath.zoom.us :
Click on "Recordings" on the left:
This will show you your recordings:
Clicking on "More" shows the option to delete a recording:
Note that this is the equivalent of moving a file to your PC "Trash". To fully delete the recording, click on the Trash link:
To fully delete a file from Trash, click on "Delete" for that recording. Alternatively, delete all recordings in Trash by clicking on "Empty Trash":