In a bowl, combine soy sauce, honey, minced garlic, grated ginger, and black pepper. Place flank steak in a resealable plastic bag and pour marinade over it. Seal the bag and refrigerate for at least 2 hours, preferably overnight.

Prepare the Teriyaki Chicken

In a separate bowl, mix teriyaki sauce with chopped green onions. Marinate the chicken breasts in the teriyaki mixture for at least 30 minutes.

Grill the Flank Steak

Preheat the grill to medium-high heat. Remove flank steak from the marinade and grill for about 6-8 minutes per side for medium-rare, or until desired doneness. Let rest for 5 minutes before slicing.

Grill the Chicken

On the same grill, add the marinated chicken breasts. Grill for about 5-7 minutes on each side, or until fully cooked and internal temperature reaches 165°F (75°C).

Serve

Slice the flank steak and serve alongside the grilled teriyaki chicken. Garnish with toasted sesame seeds and additional chopped green onions if desired.