When a user logs-in they are presented with a default dashboard that can be configured by an administrator, see the image below:

The configuration can be done on Administration -> Public Dashboards, an administrator can decide to implement a list of Public Dashboards that will be available to every user in the system.

Administrators can add and remove dashboards at will, further note a user can configure their own personal and private dashboard which they can update and delete at will.  This will have a delete button as displayed below:

Most importantly, only a Default Public Dashboards can only be deleted by an Administrator.