In a bowl, combine the yogurt, olive oil, garlic, paprika, origanum, chili flakes, and a large pinch each of salt and pepper. Add the chicken and let it marinate for 15 minutes at room temperature or up to overnight in the refrigerator.
Preheat the oven to 200°C. Arrange the chicken on a baking sheet. Bake for 25 minutes, until cooked through. Thinly slice the chicken.
Meanwhile, mix the lettuce, avocado, peppadew, dill, and feta in a bowl.
Place one tortilla at a time in the microwave for 20 seconds. Spread on a layer of pesto, then add the lettuce mix and the chicken. Spoon over some of the tzatziki.
Fold the tortilla over the filling, then fold the sides and ends of the tortillas over the filling and roll forward.