Barbecued Chicken and Chickpea Quesadillas

Name: Barbecued Chicken and Chickpea Quesadillas
Ingredients: 2 cups shredded cooked chicken; 1/2 cup bottled barbecue sauce; Sea salt and freshly ground black pepper; 1 15-ounce can chickpeas (about 2 cups), drained but not rinsed, 2 tablespoons liquid reserved; 2 garlic cloves, minced; 2 scallions, minced (white and green parts); 8 7-inch flour tortillas; 1/2 cup fresh cilantro leaves; 2 ounces smoked Gouda cheese, shredded (about 1/2 cup); 2 ounces Monterey Jack cheese, shredded (about 1/2 cup); Olive oil for oiling the grill pan