check out their menu here

an excerpt from their website -

Smørrebrød was invented by working people who had to eat their lunch away from their homes. We aim to put a modern spin on the traditional open-faced sandwich by combining new flavors and techniques. We believe that craftsmanship and local products help elevate this simple concept. Grey Duck strives to provide guests with a superior sandwich and an educational platform for the palate out of a humble food truck.