Make the Teriyaki Sauce

1. Combine all the ingredients in a small saucepan, mixing until there are no lumps.
2. Gently warm over medium-low heat, stirring frequently with a wooden spoon until slightly thickened, 1 to 2 minutes.
3. Store in an airtight glass container in the refrigerator for up to 2 weeks.

Make the Chicken Teriyaki

1. Preheat the oven to 425°F. Line a sheet pan with parchment paper and place a baking rack on top. Lightly spray the rack with oil.
2. Pat the chicken dry. Lightly season with a bit of sea salt on all sides.
3. Place the chicken thighs, skin side up, on the prepared rack. Bake for 20 minutes, or until the skin becomes light golden brown and the meat is completely cooked through (165°F on a meat thermometer).
4. Remove the chicken from the oven and brush with the teriyaki sauce. Change the oven setting to high broil. Place the chicken back in the oven and broil for 3 minutes to give the skin a nice golden color. (If you use skinless chicken, broil for only 1 to 2 minutes.)
5. Wait for 5 minutes before slicing the chicken into bite-sized pieces. If desired, sprinkle with toasted sesame seeds and chopped scallions.