Pre-heat a wok or large saute pan over medium-high heat and add oil. Stir in garlic, ginger, and chili paste until fragrant, about 30 seconds.
Add bok choy to the pan along with a pinch of salt and pepper. Saute for 2 minutes then add in soy sauce, water, and sesame oil. Saute an additional 2 minutes or until bok choy is bright green. Serve with sesame seed and scallions on top if you wish.