The answer to this is sort of yes and no...
By default, Dashboards (Panales) created by users are private, so these will only be visible to the users who created them. You can restrict users from sharing dashboards by removing the required groups from the Share Dashboards and Filters global permission in System settings, which will mean that any new boards created will only be visible to the person who created them, however you can't stop a user from creating a private dashboard, and they will still be able to see the dashboards which are already shared with them if you remove all groups from this global permission.
To prevent users from viewing the People section (Personas), you can remove the groups from the Browse Users and Groups global permission, however this means that the users in these groups will no longer be able to use any user-picker or group-picker fields across all of Jira, so I wouldn't recommend this.
Out of interest, why do you not want users to be able to view these two sections? Is it for security reasons? Or is it to prevent unnecessary boards building up to keep things tidy? Perhaps there's something else you can do to get around these