How to Make It
Heat grill to medium. Brush the chicken with 1 teaspoon of the oil and season with ¼ teaspoon each salt and pepper.
In a medium bowl, toss the scallions with the remaining 2 teaspoons of oil and ¼ teaspoon each salt and pepper. Grill the chicken, covered, until cooked through, 4 to 7 minutes per side; brush with the hoisin sauce and turn occasionally during the last 3 minutes of cooking.
After the chicken has cooked for 5 minutes, grill the scallions, turning occasionally, until tender, 2 to 4 minutes.