Which product does your user use?
Tableau Desktop or Server?
1. In case of workbook, try menu [Workbook] > Export > Crosstable to Excel
2. In case of dashboard, it's impossible to export the data of all the workbooks contained in the dashboard, into one Excel.
An alternative could be, select one worksheet in the dashboard, and do the same as 1
1. In case of workbook, try Download> Crosstab
2. In case of dashboard, similar to Desktop, select one workbook in the dashboard and do the same as 1.
There are also problems
First is that, these steps exports all the data.
While in "View Data", you can select several data marks and only view the desired data.
Secondly, exported data is in the form of crosstable.
A little not sure if the layout meets your user's requirement.
not to Excel, but to another sheet...
i.e., to display the View Data Summary results in another Dashboard/worksheet...?
You could try recreating the View Data Summary as a crosstab, and add that to the dashboard. Then, use action filters to filter the crosstab based on clicking the graphs. The last piece is to update the action filter option "Clearing the selection will:" to "Exclude all values". Then, if you select and then unselect a point on the graph, your crosstab will be empty until another point is clicked.