1) For smoking: 900g wood chips 900g all-natural chunk charcoal Place the wood chips into a bowl and cover with cool water. Set aside and allow to soak for 1 hour.
2) In the meantime, place the salt, sugar, water and red pepper flakes into an electric kettle and heat just until the salt and sugar have dissolved. Turn the kettle off and add the ice. Stir until the brine has cooled. Place the shrimp into a large ziptop bag and pour over the brine. Place in a container and set in the refrigerator until the wood chips are done soaking, approximately 45 more minutes.
3) While the shrimp are brining, heat about 900g of charcoal in a chimney starter until the coals are covered with a white ash.
4)After the chips are done soaking, drain them and set aside. Drain the shrimp in a colander and thread on 4 to 6 rounded skewers.
5) Carefully transfer the charcoal to a large, round stainless steel bowl. Cover the charcoal with the wood chips. Lay the skewered shrimp directly atop the chips making sure that the shrimp do not come in direct contact with the charcoal and that the shrimp are in 1 layer. Turn another, smaller metal bowl upside down on top of the shrimp. Cook for 15 to 20 minutes or until cooked through. Serve warm or chilled.
6) For the dressing: In a small bowl whisk together the mustard seed, dry mustard and water. Place the mustard and water mixture into a small saucepan and add the remaining ingredients. Bring to a simmer over high heat. Do not allow to boil. Remove from the heat and puree with a handheld blender for 5 to 10 seconds while drizzling with oil, leaving some of the seeds intact if desired. Pour into a glass jar or container, allow to cool, cover and allow to sit in refrigerator overnight before using. Store in the refrigerator for up to 1 month.