Coat the chicken with olive oil, lemon juice, oregano, salt and black pepper and let it stand for 20 minutes.
Heat a grill pan over medium-high heat and cook the chicken for 4 to 6 minutes per side, until marked and 165°F inside.
Rest the chicken for 5 minutes, then slice it into thin strips.
Warm the tortillas in a dry skillet for 15 seconds per side and spread each with 1/4 cup hummus.
Divide the chicken, cucumber, tomato, olives and feta evenly down the center of the tortillas.
Fold in the sides, roll the wraps tightly and rest them seam-side down for 1 minute before slicing.