Change the link title of a custom view
One way to accomplish this would be to change the view from showing content to showing fields. You can then add the fields that you want to show, title and image. 

To change the link of the title, you can add the nid as a field, hide it, and then rewrite the output of the title field to include the custom path and nid in the link. 

To find the template files of the view, you need to click on the "Advanced" tab and look for "Theme: Information". You'd need a sub-theme to register the template file being overwritten. Drupal Sub-theming

To overwrite it in a module, you could use a pre render hook and modify the rows on the result fields.