Grating the ginger and garlic used in the marinade releases more of their oils and helps them disperse evenly in the mixture. Bok choy can hide dirt between its leaves. To make sure it’s rinsed out, spread the leaves of the heads, soak the bok choy in salted water, then rinse and dry well before chopping. Stick with a neutral oil like canola oil or vegetable oil when frying the vegetables for the rice. Olive oil can overpower the aromatics and change the flavors of the rice.