You can either use the refresh attribute (http://splunk-base.splunk.com/answers/1847/how-can-i-auto-refresh-my-dashboard ) for view elements or apply an input field of type="time" where one can choose the Real Time / 30 Seconds Window option.
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Maybe this answer could help: http://splunk-base.splunk.com/answers/62516/delete-the-data-after-indexing -- Although it's still weird somehow, because one needs to stop the Splunk daemon before the operation..
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