Preheat a gas grill on medium-high heat or prepare a charcoal grill.
Lightly spray the zucchini, onion, tomatillos, jalapeƱos, and poblano peppers with cooking spray. Place on the grill for 5-7 minutes, and flip and cook 5-7 more minutes, or until the vegetable skins begin to char and the vegetables are cooked through.
Place the charred zucchini, onion, tomatillos, jalapeƱos, poblano peppers, lime zest and juice, salt, and cayenne sauce in the bowl of a food processor. Process until very smooth. Add honey, to taste, if using. Serve at room temperature.