I don't think there is an API endpoint for Dashboards at the moment. What you can do is share the dashboard via a link: https://www.dynatrace.com/support/help/monitor/
It's only possible to view Dashboards when logged in so it will ask for credentials if you aren't. The default sharing link would be something like:
But you can change the gtf parameter to any timeframe you like, e.g. for October 3rd 12am to October 4th 12am (UTC+2):
To gernerate these you can use the default timeframe utility. That will adjust the gtf parameter of the current page automatically.