It is not possible to adjust the column width on any of those pages. You can create custom views, but even those will come with a default size for the columns, that cannot be changed. See Use and Customize Views for more information on what can be done.
An alternative to list the items and be able to adjust the column width you can make use of the custom list app on a custom page.
To create a custom page:
- Hover over the tab you would like the new page to reside in.
- Click the + New Page link underneath the tab. An editor window displays.
- Enter the name of your custom page.
- If you would like to share the page, select the Share with all projects checkbox, or select one or more projects from the Share with selected projects field.
- If you would like to filter the contents of apps on the page, select one of the Show Filter options.
- Click one of the three Save options to confirm your changes.
- Click on the "Start adding apps" link on the newly created page and add the custom list app to your page.
For more information on custom pages see Custom Pages
For more information and setup of the custom list app see Custom List