In large bowl combine chicken thighs, ½ tsp. sprinkle of sumac, paprika, juice of ½ lemon and olive oil and let marinate while preparing the onions. Slice the onions. Heat olive oil in a frying pan over medium heat then add the onions. Add the sugar, Serrano pepper, salt, pepper and the sumac. While onions are cooking place the chicken in an oven safe pan and cook at 375 degrees Fahrenheit for 25 minutes with the last 7 minutes on broil. When chicken is cooked remove from pan and reserve the drippings. Heat canola oil in small pan over medium heat then add pine nuts, stirring constantly to avoid burning and remove when they are a light golden brown.
Slice chicken and place a small amount in a flour tortilla along with some and caramelized onions and pine nuts, roll to seal. Add the reserved drippings to a frying pan over medium heat then place the tortillas, seam down into the pan. Allow to heat for a few minutes or until golden brown. Remove and plate with a side of Tzatziki sauce.
To make the Tzatziki sauce, peel and slice a cucumber and remove the seeds. Add cucumber, garlic and fresh mint to 16oz. of Greek Yogurt and mix well.