Lightly spray the zucchini and peppers with olive oil, and place on a preheated barbecue. Grill until tender crisp, turning 3 times. See how to get Perfect Grill Marks, and check out the vegetable grilling guide. Once cooked, cut the peppers into strips. Whisk together the vinaigrette ingredients. On a large white platter, arrange the vegetables decoratively, with the tomatoes in the centre, the zucchini on the outside, the asparagus stacked against the zucchini, and the peppers stacked against the asparagus. Scatter the feta cheese and olives on top. Drizzle with Basil Vinaigrette.