Full bleed slideshow with offset?

Is there a way to have a responsive full bleed slideshow background that is offset by the width of the sidebar? I am setting up a site with a sidebar where the z-index is set to sit on top of the background, but the images in the slideshow background have their left side cut off as a result.

I want the left side of the image to be flush with the sidebar’s edge, rather than flush with the browser window edge. Possible?

I am using WP Supersized for the slideshow. Can anyone recommend a fix or an alternate plugin? Thanks!