Clean and dry the shrimp well. Place half of the flour in a shallow dish.
Whisk together the remaining rice flour, cornstarch, and baking powder. Add half of the sparkling water, stir. Add more as needed to make it a medium-thick batter. To test, dip in a spoon. The batter will be thin, but still should thickly coat the back of the spoon rather than running completely off. Imagine a thin pancake batter. If it is too thin, add more flour a tablespoon at a time until it is just thick enough to coat the back of a spoon.
Pulse the brown rice puffs in a food processor until they are in itty-bitty pieces, but not a fine powder. Alternatively, use panko breadcrumbs. Place these crumbs or the panko crumbs with the shredded coconut in a separate shallow bowl.
Add a pinch of salt to each of the three bowls. Toss each.
Be sure the shrimp is cleaned and deveined (they can be purchased this way, or using a paring knife gently cut into the dark vein and scrape it out). Leave the tails on to use a handle for dipping and eating.
Dip the shrimp in the flour, shake off the excess. Next, dip it into the batter, drip off the excess. Then press the wet shrimp into the coconut-crumbs. Tap off the excess and lay on a baking sheet to dry slightly.
They can be frozen at this point and fried later. Or fry them up now.
Coat the bottom of the pan with about a generous 1/2 inch layer of oil and warm over medium heat. Drop in a dollop of batter, when it floats up in about 10 seconds add in the coconut shrimps about 3-6 per time, do not overcrowd the pan.
Turn over once golden after about 2-3 minutes (use tongs, slotted spoon or a metal spatula for flipping). Once hot and golden on both sides, set aside.
If you rather skip the frying, heat your oven to 425. Warm the coconut oil just until melted. Dip the shrimp on each side for a light coating of oil. Spread on the baking sheet lined with foil or parchment paper.
Bake for about 3 minutes. Flip over and continue to bake another 2-5 minutes until the shrimp is cooked through and lightly golden. To test the shrimp, pull one out and cut into it. It will appear white and cooked through, lightly firm, but not hard.
When it is cool enough to bite, that is the best way to taste test them. Pull out and serve hot.
These shrimp can also be fried up in advance and briefly reheated at 450 for about 3-4 minutes until hot in the center.