Here's the adjacent wall.

What is the distance from the edge of the table to the wall you are asking about decorating?

There's only 18" from the back of the chair (when someone is sitting in it) to the wall. We need the 6 chair seating, so I can't switch out the table. I've also considered rotating the table, but then it blocks the walkway.

Given that spacing, a large piece of art would look great on that wall (no table or sideboard). Art width around the table width or a bit wider and art height not taller than the top of the doorway on the right.

My preference would be for the art to be centered on the wall and for the table to be centered on the wall & art. Is it feasible to pull the table away from the window a bit to center it on the wall or does that put the chairs on the kitchen side into the walkway? I don't see a chandelier above the table that would be affected by moving the table a bit.

The photos posted by @kandrewspa are two really great examples for your room!

is there an out let for a ceiling light?

Thank you for the feedback! I am planning to add a chandelier, I just haven't figured out what one yet. And I will shift the table to be centered on the wall- I didn't realize it wasn't. I taped out dimensions of 48x60. Does that look about right? Should the art be vertical or horizontal? The example pics are beautiful and the art looks more vertical.

if you are planing on a light fixture I would do that first, it will have impact.