Separate bok choy leaves from stems. Slice stems into 1-inch pieces; chop leaves.
Combine water, rice, and soy sauce in a pot; bring to a simmer and stir in bok choy stems. Reduce heat to low, cover the pot with a lid, and cook until rice is almost cooked through, about 18 minutes.
Stir bok choy leaves, chili-garlic sauce, and sesame oil into rice mixture with a fork. Remove pot from heat, cover the pot with a lid, and let sit until rice is cooked through and bok choy leaves wilt, about 5 minutes more. Fluff with a fork and garnish with sesame seeds.