I incorrectly created a dashboard
There should be a "Manage Pages" link at the bottom of your Dashboard list:
From there, you will be able to delete the page, or dashboard that you created.
Only gave option to add pages.
Under Admin -> Pages you can filter for the page you want (clicking on the ... in each column) and then select the page. In the upper right hand corner there will be an Edit button. You can select Delete Page from the drop down list.
Yes, the steps remove pages, but not dashboards.
Did you convert a page to a dashboard or are you talking about a quick start app?