Heat the oil in a large skillet or wok over medium-high heat. Season the pork with salt and pepper, and sauté the pork in two batches, for 3 minutes each, until browned and almost cooked through. Transfer the pork to a plate as each batch is finished.
Return the pan to the heat, and add the remaining tablespoon oil. Add the bok choy and sauté for 2 minutes until it begins to wilt. Add the soy sauce, chili garlic sauce, scallions, and ½ cup water to the pan, and continue to cook for 1 more minute, stirring frequently, until the sauce has blended nicely and coats the bok choy. Return the pork to the pan and cook until the pork is cooked through, about 1 more minute, and everything is well combined.
Serve hot with the rice of your choice.
Notes
Start the rice before the stir-fry so it's done by the time the stir-fry is cooked.
Don't be tempted to combine the ingredients in the pan all at once — they will steam instead of browning.
Instead of pork, you could use chicken, beef, or extra-firm tofu. Or could also use shrimp — if they are jumbo, the cooking time is about right. For smaller shrimp, you may need to reduce the initial cooking time or just cook them through and add them at the very end.
Try other greens instead of bok choy, like small broccoli florets or pieces of asparagus.