We've often seen this done in tiny restaurants, but not so much in homes. A mirror is placed on the wall at about the eye level of seated diners. The effect is expansive and lively: the dining space is opened up and the space feels like it continues beyond the mirror's surface. When browsing Montreal-based Moutarde Décor's website, we noticed they applied this trick in many small residential dining spaces...

Two of these arrangements pair a mirror with banquette seating. We think that would be a great application for small-space living. The mirrors work to reflect the dining surface, light fixtures, and windows' natural light. See more at Moutarde Décor.