Step 1

In a 12-inch skillet, combine the sugar and 2 tablespoons coconut water. Cook over medium-high, occasionally swirling the pan to help the sugar dissolve and to encourage even browning, until the caramel is mahogany in color and smokes lightly, 4 to 6 minutes. Remove the pan from the heat and add the fish sauce along with the remaining 2 tablespoons coconut water; the mixture will bubble vigorously and the caramel will harden in spots.

Step 2

Bring to a simmer over medium and cook, stirring, until the hardened bits have dissolved. Add the chilies, shallots, lemon grass, ginger and 1 teaspoon pepper; cook, stirring, until fragrant, about 30 seconds. Increase to medium-high and stir in the pork. Bring to a simmer and cook, uncovered and stirring occasionally, until the sauce reduces and clings to the pork, 10 to 14 minutes.

Step 3

Off heat, remove and discard the lemon grass. Transfer to a serving dish and sprinkle with the scallions. Serve with lime wedges.