Yes, you can delete any Project (now known as Sites in version 5.0) in Settings > Site Admin
For version 4.7:
- from the main Project listing page, click the name of the Project you wish to delete
- from the Project page, click the Settings button in upper right
- click Site Admin in sidebar navigation
- at the bottom, click Delete button
For version 5.0 Preview:
- from the main Site listing page, click the name of the project you wish to delete
- from the Site page, click the Site Settings button in upper right
- click the Site Admin tab
- at the bottom, click Delete button