In 3.2.x and 3.3.x, dashboards refresh automatically on their own schedule: 10% of the time period or 1 hour, whichever is sooner. You can’t change this right now. But if you want to force a refresh, you can delete the files that contain the cached data.
Dashboards create username_* files in $SPLUNK_HOME/var/run/splunk to persist the dashboard data. There is also a directory for each username with *.csv files. Delete the username_* files (like “admin_KB indexed per hour last 24 hours”) and the *.csv files and the next time you refresh the dashboard, it will reload.
This is not an elegant solution by any means, but it does work. While you could just delete the files for the search in question, there is no simple way to identify which csv file is associated with it. Just don’t go messing with the other files in this directory, you will be Very Unhappy if you do.