Whisk soy sauce, rice vinegar, chili-garlic sauce, honey, sesame oil, cornstarch, and 2 tbsp water until smooth.
Rinse bok choy well, separating stems from leafy tops. Pat dry to avoid splatter.
Heat a large skillet over high heat. Add neutral oil, then stir-fry ginger and garlic for 30 seconds until fragrant.
Add bok choy stems. Cook, stirring often, until crisp-tender, about 2 minutes.
Add bok choy leaves and the remaining 1 tbsp water. Toss until just wilted, 1 to 2 minutes.
Pour in the ginger-chili sauce. Stir until glossy and slightly thickened, about 1 minute.
Finish with scallions, sesame seeds, and red pepper flakes if using. Serve hot.