Preheat a grill or grill pan over medium heat.
Toss zucchini, bell peppers, onion, and mushrooms with olive oil, garlic powder, oregano, salt, and pepper.
Grill vegetables for 5 to 7 minutes, turning occasionally until tender with slight char marks.
Warm tortillas briefly on the grill or in a pan.
Spread each tortilla with hummus or yogurt, then layer with grilled vegetables, spinach, and feta if using.
Roll up tightly into wraps, slice in half, and serve warm.