This is a great way to use up last-of-the-season garden vegetables. As soon as the pan gets hot, add enough zucchini cubes to form a layer on the bottom of the pan. Cook over high heat, stirring, until zucchini is lightly browned on all sides. Remove zucchini cubes, and add them to pan with the onions. Repeat process until all of the zucchini cubes have been cooked.