You can override the existing layout. For example copy clients/base/layouts/record/record.php to custom/clients/base/layouts/record/record.php and remove the section related to the dashboard-pane. this will then remove dashboards from all record views.

This can also be done for a single module instead of the entire application.

As a developer, you can extend all layouts. 

However, I would advise against removing the dashlet-pane as there is so much functionality that can be added in this pane. This is also the recommended place to add new functionality!