Shingle the zucchini slices in a single overlapping layer on a platter. Dust with salt and pepper, then drizzle with a 3-count of olive oil and the lemon juice. Put that into the refrigerator for about 10 minutes to give the flavors a chance to get into the zucchini. Now scatter the leeks over. Sprinkle with the herbs. Then garnish with the ricotta cheese and mint leaves, if using.