Slice the bok choy in half lengthwise, or into quarters if large. Rinse under running water, gently pulling apart the stalks to remove any dirt. Shake off excess water. Chop stalks into ½ to 1 inch pieces and separate them from the leaves. Chop the leaves separately. Heat oil in a large pan over medium heat. Add minced ginger and garlic, frying for about 30 seconds while stirring. Add the bok choy stalks and half the salt, stirring to coat in oil. Cook for about 5 minutes until stalks are soft and translucent, stirring occasionally. Add bok choy leaves and remaining salt. Cook for an additional 1 to 2 minutes until leaves are tender and bright green. Serve hot as a side dish.