Soak wooden skewers in water for 30 minutes minimum while you prepare the glaze. Combine honey, minced garlic, soy sauce, olive oil, rice vinegar, ginger, red pepper flakes, and brown sugar in a small saucepan over medium heat. Stir constantly until the mixture becomes fragrant and slightly thickened, about 3-4 minutes.

In a small bowl, whisk together cornstarch and water to create a slurry. Pour the slurry into your saucepan while stirring continuously until the glaze coats the back of a spoon and reaches honey-thick consistency, about 1-2 minutes. Remove from heat and stir in sesame oil. Let cool for 5 minutes before using.

Pat chicken pieces dry with paper towels and season generously with salt and pepper. Thread pieces onto soaked skewers, leaving ¼-inch space between each cube so heat circulates evenly and they cook through uniformly.

Preheat your grill to medium-high heat (400°F) and lightly oil the grates. Thread sticky honey garlic grilled chicken skewers onto the prepared grates, spacing them 2 inches apart to prevent crowding.

Grill for 4 minutes on the first side without moving, allowing caramelization. Flip carefully, brush immediately with glaze, and grill the second side for 3-4 minutes until the internal temperature reaches 165°F.

On the final minute, brush the first side with remaining glaze and flip once more, allowing the coating to caramelize and set. Transfer to a clean platter and garnish with chopped green onions. Rest for 2 minutes before serving.