How to Make It
Whisk together lime juice, fish sauce, brown sugar, 1 tablespoon of the oil, and, if desired, red pepper in a small bowl until sugar dissolves; set aside.
Heat remaining 2 tablespoons oil in a large skillet over medium-high. Add garlic and half of chile slices; cook, stirring constantly, until fragrant, about 10 seconds. Add pork, salt, and black pepper; cook, stirring to break pork into large pieces and pressing down firmly to crisp, until browned and starting to char, 8 to 10 minutes. Remove from heat; stir in 2 tablespoons of the lime juice mixture.
Thinly slice bok choy stalks on the diagonal; cut leaves into 1½ -inch-wide strips. Combine bok choy slices and strips, carrots, scallions, and cilantro in a large bowl. Add remaining lime juice mixture; toss to coat. Serve pork over bok choy mixture. Top with peanuts and remaining chile slices.