Heat olive oil in a skillet over medium heat. Add zucchini and bell pepper. Sauté for 3–4 minutes until just tender. Stir in spinach, Italian seasoning, salt, and pepper. Cook for 1 more minute, until the spinach has wilted.
Lightly toast pita halves in a dry skillet or toaster oven for a bit of crunch.
Spread hummus or avocado inside each pita half if using. Fill with the warm veggie mixture and top with shredded cheese.
Return stuffed pitas to the skillet or sandwich press for 2–3 minutes, or microwave for 30–60 seconds until cheese is melted.
