In TimeTracker, Projects are not deleted. They can be hidden or removed from your active list by clicking on the gear icon in the Projects section on the right side of the browser experience. (See screenshot below)
Clicking on the gear will bring up the My Projects window.
To hide/unhide the Project, click on its corresponding eye icon in the My Projects window.
To remove the Project from your list, click on its corresponding red 'x' in the My Projects window.