Serves 6
2 tablespoons cumin seeds
4 scallions (3 roughly chopped, 1 thinly sliced)
1 jalapeño pepper, roughly chopped (remove seeds for less heat)
1 2-inch piece ginger, peeled and roughly chopped
1 clove garlic, roughly chopped
3 tablespoons vegetable oil, plus more for brushing
1 tablespoon packed light brown sugar
¼ cup plus 2 teaspoons soy sauce
1 teaspoon Chinese five-spice powder
Kosher salt and freshly ground pepper
2 pork tenderloins (about 1½ pounds total), trimmed and cut into 1½-to-2-inch pieces
¼ cup rice vinegar (not seasoned)
1 teaspoon toasted sesame oil
Soak 12 long wooden skewers in water, at least 30 minutes. Meanwhile, toast the cumin seeds in a small skillet over medium heat, swirling the pan, until slightly golden, about 4 minutes. Transfer to a plate.
Combine the 3 chopped scallions, the jalapeño, ginger, garlic, 1 tablespoon vegetable oil, the brown sugar, 2 teaspoons soy sauce, the five-spice powder, ¾ teaspoon salt and ½ teaspoon pepper in a food processor and pulse until a paste forms. Add the toasted cumin seeds; pulse once or twice to crack them slightly.
Lightly season the pork with salt and pepper; rub with about three-quarters of the cumin paste. Cover with plastic wrap and refrigerate at least 30 minutes and up to 1 hour.
Meanwhile, make the sauce: Combine 1 teaspoon of the remaining cumin paste, the remaining ¼ cup soy sauce, the vinegar, sesame oil and 1 tablespoon water in a small bowl. Stir in the sliced scallion and set aside.
Preheat a grill to medium. Combine the remaining cumin paste and 2 tablespoons vegetable oil in a small bowl; set aside for basting. Generously brush the grill grates with vegetable oil. Thread 3 or 4 pieces of pork on each skewer and brush with vegetable oil. Grill the kebabs, turning, until marked all over, 6 to 9 minutes, basting with the cumin-oil mixture during the last minute. Let rest 5 minutes before serving. Drizzle with the sauce.