Dark wall, with dark wood furniture illuminated with warm lighting does not make the space seem narrow, as one would imagine, rather it makes the whole area appear quite warm and cozy. The black chairs complement the black wall, and the bench is definitely the center of attraction of this open dining space.
Dining tables and chairs absolutely need to be proportional with each other, as there's no use in having a low table and tall chairs! For a pared back, organic and very zen installation, Japanese designs can be looked to for inspiration, with tatami mats housing a low table and numerous floor-mounted seats. With back supports in place, comfort AND relaxation will be combined to perfection.