Disable the Finder module (according to the user ?) and change the way the Assets module works

You can define user-group permissions in your config.php. To disable the ‘finder’ module for a group use

{
  groups: {
    noFinderUsers: { // your groups name
      cockpit: {
        finder: false
      }
    }
  }
}

Currently not. This is hardcoded in the assets module