As mentioned in another recent post, C# is not the best choice when you are looking for a very small memory footprint. C# is very efficient when handling very rich functionality.
Looking at the memory footprint with one small form running is akin to asking "why does my V-8 truck burn so much gas when I'm only hauling a few groceries?" Haul groceries in a Honda. Use the truck for hauling furniture, rocks, and other vehicles.