How to Make It
In a large bowl, mix 1/2 cup of the coconut milk with 1 tablespoon of the fish sauce, the coriander, curry powder and 1 tablespoon of brown sugar. Add the pork and let stand, turning occasionally, for 10 minutes.
In a small saucepan, combine the vinegar with the remaining 1/3 cup of brown sugar and 1/2 teaspoon salt. Simmer over moderate heat, stirring, just until the sugar dissolves. Add the chiles. Pour the dressing into a medium bowl and let cool.
Light a grill or preheat a cast-iron grill pan. Grill the pork over moderate heat until browned all over and firm to the touch, about 15 minutes for medium. Transfer to a cutting board, cover loosely with foil and let stand for 10 minutes.
Meanwhile, heat the oil in a medium skillet. Add the shallot and cook over moderate heat until softened, about 2 minutes. Add the peanut butter, red curry paste and the remaining 1 1/4 cups of coconut milk and 1 teaspoon of fish sauce. Simmer over low heat until slightly thickened, about 2 minutes. If the sauce breaks, whisk in the boiling water. Add the lime juice and season with salt.
Add the cucumbers to the dressing and toss, then add the cilantro and basil. Mound the cucumber salad in the center of a large platter. Thinly slice the pork and arrange around the cucumber salad. Sprinkle with the salted peanuts and serve the peanut sauce on the side.