How to Make It
In a small bowl, combine the salt with 1 tablespoon of the sugar. Sprinkle the salt-sugar all over the pork belly. Wrap the pork in plastic, transfer to a plate and refrigerate overnight.
Preheat the oven to 375°. Rinse the pork and pat dry. Set the pork in a small baking dish, fat side up, and add 1/2 cup of water. Bake for 45 minutes. Reduce the oven temperature to 325° and bake for about 45 minutes longer, until the meat is very tender. Let the pork cool, then cover and refrigerate until chilled, at least 2 hours.
In a saucepan, cook 1/4 cup of the sugar over moderately high heat until it starts to melt, 2 minutes. Swirl the pan and cook over moderate heat until it is completely melted, 5 minutes. Using a wet pastry brush, occasionally wash down the side of the pan to release any sugar crystals. Add the remaining 1/4 cup of sugar and cook, swirling, until a richly brown caramel forms, 5 minutes. Turn off the heat and pour in 1/3 cup of water. Turn the heat to high and cook, stirring, until the caramel is smooth. Remove the pan from the heat and stir in the fish sauce, tamarind, chile and lime juice.
In a large bowl, combine the lime juice with the fish sauce, sugar, chile and 2 tablespoons of water; stir to dissolve the sugar. Add the honeydew and toss to coat. Refrigerate for 1 hour, stirring a few times.
Preheat the oven to 400°. Cut the cold pork belly into 1 1/2-inch cubes. In a medium cast-iron skillet, heat the caramel over moderate heat. Add the pork and turn to coat with caramel. When the sauce starts to bubble, transfer the skillet to the oven and bake for 20 minutes, turning the pork 3 or 4 times until the cubes are evenly crisp.
Using a slotted spoon, transfer the pork belly to plates. Spoon the caramel over the pork. Add the basil to the honeydew salad and spoon it next to the pork. Sprinkle with the cashews and serve.