Place the sliced zucchini in a colander that is set over a bowl. Sprinkle with the salt and toss well to combine. Allow the zucchini to sit for 10 minutes.
Meanwhile, in a medium saucepan, combine 1½ cups of water with 1½ cups of apple cider vinegar and bring to a boil over high heat. Add the salted zucchini to the pot and return the mixture to a boil. Reduce the heat to maintain a simmer and cook for 4 to 5 minutes, or until the zucchini is cooked through but still has a little texture. Drain the zucchini and place it in a large bowl.
Add the remaining 1 tablespoon vinegar, the mint, basil, garlic and red pepper flakes to the zucchini, and toss well. Add enough olive oil to cover the zucchini and allow the mixture to cool to room temperature. Pack the zucchini in jars or a storage container with a tight-fitting lid, making sure the zucchini is fully covered with the oil. Store in the refrigerator for up to 3 weeks. Serve at room temperature.
