To give people view access to the spreadsheet, go to the “Publish” tab of the sharing menu, click the publish button and enable the option “Allow access to spreadsheet”.
Sharing the dashboard with a set of users and allowing spreadsheet access just to a subset is not possible as of now but it can be worked around easily.
To accomplish this, create a new model and import all charts that belong to the primary model.
The new model can be used to share the dashboard only view whereas the primary model can be used with the view only spreadsheet.