Microwave the beans for about four minutes—this will keep them crisp while you cook them on the stove.
Heat a bit of olive oil in a saucepan and add garlic when the oil is hot. Add the beans when the garlic is slightly brown, and add oyster sauce and a pinch of sugar to taste. Stir on medium heat until the beans are slightly pliable. (Taste a few of the beans to make sure they've taken on enough of the oyster sauce flavor.)