In a saucepan over low heat, dissolve sugar in vinegar and keep warm. Wash zucchini and cut into 1/4-inch rounds. Fry a few at a time in hot oil over high heat (check oil temperature with a piece of zucchini).
Arrange rounds in a baking dish. Season with salt to taste and cover with sweet and sour marinade. These zucchini are wonderful in the summer and can be eaten warm or cold.