Try centering it over your table, and then place a tall plant in the corner to balance everything out.

I would put a tall floor plant in the corner to decrease the expanse of the wall. Then, I think you would work with the placement in the middle of the remaining space. See how that works. Can you run your table the other way?

then I would have 2 pictures facing each other- the living room is across the foyer from the dining room and has this big canvas (which hasn’t been hung yet)

I'd think about a gallery wall with pics in the same colors in the dining room.

But would you center the gallery wall with the table? Or with the wall? That’s what I’m so unsure about. I feel like either way, it will look off.

Have the gallery take up most of the wall and you won't have to worry about how it's centered.

I often agreed with Sophie, but I don't think I've ever seen a DR that didn't have a lovely mirror in it somewhere. I've always had one in mine. One does not "look in" such a mirror - it is to reflect light, a lovely table, flowers, silver etc. Dining rooms typically are lit for dinner parties with a dimmer on the chandelier, and lots of candles, both on the table as well as the sideboard and any other cabinet furniture in the room.

If you use one large art print and on the opposing wall use an antiqued mirror. The reflection is softened.