For the sauce: In a saucepan dissolve the cornstarch in water, turn the heat on medium high; add the vinegar and bring to a boil. Stir in honey, ginger, garlic, red pepper flakes, and lime juice; simmer for 3 - 5 minutes until it starts to thicken and bubbles. Pour into a bowl and refrigerate until ready to serve.
In a pot heat the oil on medium heat. (Make sure the oil is hot)
In a bowl, mix together the flour, baking powder, coconut, and pinch of salt. Slowly whisk in the seltzer a little at a time until the batter becomes thick and smooth. (dont pour all of the seltzer in at once you may not need it all)
Coat the shrimp in cornstarch and then dip into the batter (allowing the excess to drip off) and then slowly immerse the shrimp into the hot oil. Work in batches if needed as to not overcrowd the oil.
Cook for 3 - 5 minutes until golden brown. Drain on a paper towel lined plate and serve.