Within Teamwork Projects, you can delete a project at any stage (permissions dependent) from the 'Overview' area within a project.
To do this, navigate to the overview area on the project you want to delete:
Click the options button (three dots) to the top right of the page, and select Delete from the Manage Project tab:
Once you delete a project it will be moved to the trash can for 30 days however this can be restored within this time frame.
For more information, see: Viewing and restoring deleted projects