With this wordpress theme you can change the display settings of the pages, but you can't change the display settings for the items.
If you remove the sidebar and select the page view to full screen, you'll see the post with a blank space on the right where it was before the sidebar.
I found the solution and I decided to share it with you because there are many sites that explain it well this thing.
The solution however is simple, you just enter in the phase of customization of the theme, in the section CSS the following code:
I hope that this article has been helpful. Ricorca that this method reduces the size to the point that it becomes invisible. You may then have problems with the display using some plugins that are not able to manage the thing.