In a large bowl whisk together the olive oil, lemon zest, lemon juice, parsley, garlic, cumin, salt, and paprika. Add the chickpeas and stir to combine. The longer the chickpeas marinate, the better they taste, so if you have time, cover and refrigerate for at least an hour and up to a couple of days.
In a separate bowl combine the yogurt and mint. Again, this is better if it sits for awhile, so cover and refrigerate if not using immediately.
Cut pita breads in half. Line each half with chard or other greens, then fill with tomatoes, chickpeas, and onions. Garnish with parsley and mint, if desired. Serve with minted yogurt spooned on top.