Remove Sidebar Widgets

I’m trying to remove the Sidebar widgets from my site: https://kevinpdonovan.com/

Doing so through the Customizer didn’t work. So, I followed some instructions I found in the forums and removed the Sidebar code through the Editor. That seems to have removed the widgets but not the blank space of the sidebar.

My goal is to mimic the style that the Motif theme has when selecting it: a full-width featured image with a smaller block of text. I have the featured image but the sidebar prevents it from being full-width.

Thanks.