Hello,
You would need to customize the following control and its code behind: ~\CMSModules\Content\Controls\UserContributions\ContributionList.ascx
By default, the editing form is displayed only after the new document link has been clicked. Therefore, you need to hide this button and the code that gets executed in its click handler (the btnNewDoc_Click method) move to the Page_Load method for example.
Please let me know if you have any additional questions.
Best Regards,
Sandro