Preheat the oven to 450°F. Preheat a grill to high heat.
Sprinkle the seasoning and garlic powder evenly over the chicken. Place the chicken on the grill rack. Reduce the heat to medium. (If it is not possible to reduce the heat, cook the chicken away from direct heat.) Grill for 3 to 5 minutes per side, or until no longer pink and the juices run clear. Transfer to a cutting board and let stand for 5 minutes. Chop the chicken into bite-sized pieces. Set aside.
Meanwhile, place the pita on the grill rack. Cook for 1 to 2 minutes per side, or until lightly toasted. Place the pita on a nonstick baking sheet. Spread evenly with the hummus. Top evenly in layers with the beans, the reserved chicken, onion, red pepper, tomato, cilantro, and cheese.
Bake for 6 to 8 minutes, or until the cheese is melted. Let stand for 5 minutes. Transfer to a serving plate. Slice into 4 wedges. Top each wedge with a teaspoon of guacamole or sour cream, if desired.
Source: Devin Alexander from the Biggest Loser Cookbook