Place a medium saucepan over high heat. Half fill with water and bring to boil. Turn off and add the vermicelli noodles. Let sit for 5 minutes or until softened.
Place mince, garlic, ginger, coriander, hoisin sauce and zest in a bowl, mix to combine.
Toast coconut in an empty non-stick fry pan over medium low heat and continuously stir for 3-5 minutes or until toasty brown. Transfer to a plate.
Return pan to medium high heat and add beef mixture and cook until browned. Break up any lumps and add the water chestnuts.
Add fish sauce, lime juice and ½ cup of coconut. Season with salt and pepper. Transfer mixture to a bowl and cover to keep warm.
Prepare the flatbread and toast to warm.
On an extra large plate, place noodles and lettuce. Spoon over mince mixture and top with cucumber, chilli, coriander/cilantro and remaining coconut. Serve drizzled with extra hoisin sauce.