Add zucchini and red pepper to baking pan and add olive oil, salt, pepper.Place on grill and spread evenly. Grill for 7 minutes, flipping when grill marks appear.After 3 minutes, add mango, and grill for 4 minutes, stirring so that pieces don't stick to grill.
Remove all grilled items from grill and assemble tacos with zucchini, red pepper, tomato, leeks (or green onions) and mango.