Coat an outdoor grill or stove-top grill pan with cooking spray and preheat to medium- high.
Lay out 3 chicken strips, about 1/2-inch apart. Place a scallion crosswise over the center of the chicken pieces. Then wrap chicken over scallion 1 by 1, securing with a toothpick. Repeat process until you have used 1 pound of chicken.
Season and grill the remaining 1 pound chicken breasts for another meal later in the week.
In a small bowl, whisk together soy sauce, honey, sesame oil, ginger, and garlic powder. Reserve half a cup of the marinade to use as a dipping sauce. Brush the remaining marinade all over the chicken-scallion skewers.
Grill kebabs 5 to 7 minutes turning occasionally until the chicken is cooked through.
Garnish the reserved dipping sauce with sesame seeds and serve alongside skewers.