In a large bowl, combine zucchini, garlic, basil, tomatoes, olive oil, capers, olives, lemon juice, pepper flakes, and salt. Allow to stand in cool place half hour.
Meanwhile, bring 6 litre water to boil in spaghetti pot and add 2 tablespoons salt. Drop penne in and cook according to package instructions until al dente, about 10 to dozen minutes. Drain pasta in colander and add pasta to cool vegetables in mixing bowl. Stir gently to mix well and serve immediately.
This dish is not served hot!!