How to Make It
In a blender, combine the Thai chile, garlic, ginger, water, sugar, white vinegar, flour, ketchup and 1/8 teaspoon of sea salt, and blend on high for 1 minute. (see Note). In a small saucepan, bring the mixture to a boil over high heat. Boil, whisking, for 3 minutes, until the sauce thickens. Remove from the heat and allow the sauce to cool completely.
In a medium bowl, whisk together the coconut and 1/4 teaspoon of sea salt.
Rinse the tilapia under cold running water and pat dry with a paper towel. Drizzle the lime juice over the tilapia, and then dip the fish into the coconut, pressing on the coconut so that both sides of each fillet are well coated.
In a medium nonstick frying pan, heat the oil over medium heat. Add the fish, shaking the pan gently after adding each piece to prevent sticking. Cook the tilapia for 3 minutes per side, until the coconut is crispy and the fish is cooked through.
For a smooth sauce use either a high-powered blender or strain the sauce through a fine mesh sieve after blending in a standard blender.