This can be done from the
Sharing tab of each.
(Note: if you do not see the sharing tab it means you are not running in a user enabled mode).
By default when you create a new (or duplicate an existing) data cube or dashboard the sharing permissions will be set
such that everyone can view but only you can edit. These access permissions only apply to
user level users,
super-admin users can always view and edit all resources.
It is possible to restrict access to only specific people.