Place the sliced zucchini in a colander over a bowl and toss well with the salt. Allow the zucchini to sit for 10 minutes.
Meanwhile, in a medium saucepan, combine the 1 1/2 cups of vinegar and the water 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 medium to maintain a simmer and cook until the zucchini is cooked through but still has a little texture, 4 to 5 minutes. Strain the zucchini and place in a large bowl. Add the basil, mint, sliced chili, garlic and remaining 1 tablespoon of vinegar. 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 remains covered with the oil. Store in the refrigerator for up to 3 weeks. Serve at room temperature sprinkled with a pinch of flaky sea salt.