You can set the start up defaults via the URL, including when linking to a specific dashboard. To set the refresh interval in the URL, you can specify refreshSeconds=XX as shown below:
The above is taken from the Startup Defaults section of the user guide.
To do the same when loading a particular dashboard, you will need to use a slightly different URL than the link generated by Xtraction. Using your URL as an example, when Xtraction loads the URL it will change to the following (notice the page changes from Dashboard.aspx to Default.aspx):
To add a refresh interval, you can add &refresh=true&refreshSeconds=60 to the end of this URL: