We need to see the entire wall, and the room as well.

I personally do not like art work in a kitchen. I don't think it's the place for it. In addition to being beautiful, kitchens should be functional (so I like to decorate with things that make sense, things that would be found in a kitchen) and they should be sanitary (so things likes art and rugs do not belong there). Sconces also do not belong in a kitchen because they do not produce the correct lighting and for sanitary reasons and safety (something sticking out of a wall). Without pictures, I would say if it's a large wall with nothing on it, make that an actual functioning space in some way with a bakers rack or a spice rack or something that makes sense that it would be in a kitchen.

I would guess that a 38" wide picture (wider after it's framed) is probably about the right width for that wall, so no, do not hang anything else there. It should have plenty of wall around it so it can breathe. I would also hang it just above the top of the chairs. Art goes at eye level, in this case, sitting eye level.

Like so: