Cut the Chicken Thighs into 1–1.5 inch bite-sized pieces and pat them dry with paper towels.
Trim and cut the Scallions into 1.5–2 inch lengths so you can alternate them with the chicken on the skewers.
If using wooden skewers, soak them in water for 20–30 minutes to prevent burning; then thread the chicken and scallion pieces onto the skewers, leaving a little space between pieces for even cooking.
Make the tare (glaze): combine 1/2 cup Soy Sauce, 1/4 cup Mirin, 1/4 cup Sake and 2–3 tablespoons Granulated Sugar in a small saucepan. Bring to a simmer and reduce over medium-low heat for 5–8 minutes until slightly thickened and glossy. Remove from heat and let cool slightly.
Lightly season the skewers with a small pinch of Fine Salt just before grilling.
Preheat a grill or broiler to medium-high and oil the grates or rack. Place the skewers on the grill and cook about 2–3 minutes per side until they begin to brown and are nearly cooked through.
During the last few minutes of cooking, brush the skewers generously with the tare and turn frequently, allowing the glaze to caramelize without burning. Repeat basting 2–3 times for a glossy, sticky finish.
Serve the yakitori hot, with extra tare on the side for dipping and an optional final sprinkle of Fine Salt to taste.
