The creator of a dashboard has the ability to delete the dashboard from the "Dashboard Actions" drop down.
When you are viewing a dashboard you have created, select the "Dashboard Actions" dropdown and select "Delete this Dashboard".
A message will show for you to confirm if you want to delete the dashboard.
If you confirm that you would like to delete the dashboard, the dashboard will no longer exist.
If you delete this dashboard, you will not be able to recover it again.
If you want a similar dashboard to this, you will need to recreate it.
If your dashboard is a Company Dashboard, your team will no longer have access to it.