Cut zucchini into 1/4-inch thick rounds. In a colander, toss slices with salt, top with a weighted plate, and let sit 30 minutes. Meanwhile, prepare dressing: In a small bowl, whisk together vinegars, sugar, oil, garlic, oregano and pepper flakes. Season to taste with salt and pepper. Let stand at least 30 minutes.
Rinse zucchini in running water, drain on paper towels and carefully pat dry. Divide into 12 piles. Heat oil in a wok to 375 degrees. When oil is hot, add one batch of zucchini and fry, turning each slice several times, 1 minute or until light brown. Scoop up zucchini with a slotted spoon and drain on paper towels, blotting well to absorb excess oil. Repeat until all zucchini is cooked. Remove garlic cloves from dressing. In a bowl gently toss zucchini with dressing. Let salad cool to room temperature and serve immediately or refrigerate up to 24 hours. Bring to room temperature before serving.