1) No, opening a dashboard will require a "click". (With an exception for the landing-page.)
2) Users have access to all dashboards for which they have the necessary read/write permissions for all elements on that dashboard. So if you restrict their access for a module used they should no longer have access. Note: this is considerably easier in the new UX as you can set access by role.
Thanks for your explanation, @MaartenGijbels. Appreciate it. I am putting the details here based on our email conversations to close off. Please feel free to correct as necessary.
1) One would have to click on each individual dashboard. 2) There might be a situation that there are different Saved Views for the same module to be given to different roles. By virtue of having access to the module, they can invariably open a DB which they should not. But because they have access to the module, they could open it. That's why I asked if there is a way to restrict this access.
One way to resolve this is to use the content panel to "guide", the users to the correct dashboards. (Not display dashboards that aren't relevant.)
You can open multiple dashboards with a single click via the functional area in the contents page. In the example below, when I click "SETUP", it opens both the Process Dashboard and the New Dashboard at the same time.