In jar with tight-fitting lid, combine all vinaigrette ingredients; shake well.
To partially cook cauliflower, plunge into rapidly boiling water for 1 to 2 minutes; drain. Place in large bowl. Pour vinaigrette over warm cauliflower. Add zucchini, onions and olives; toss gently. Cover; refrigerate at least 2 hours to blend flavors.
To serve, add salad greens to cauliflower mixture; toss gently.