Trim fat from 6 whole skinless boneless chicken thighs and cut each thigh in half
Season with kosher salt and sprinkle with 1 tbsp ground chili powder and then fold each piece in two, with the smooth side (presentation side) of the chicken showing. Skewer each piece onto a wooden skewer. You should allow for 4 pieces of chicken per skewer. Alternate the chicken with the white parts of one bunch of scallions cut about 1" long between each piece of chicken.
Drizzle canola oil over the chicken, turning each skewer until all sides have been coated in oil.
Pre heat oven to 450℉
Place skewers on an aluminum foil lined flat sheet and lay the skewers over the edges of the pan to keep them off the foil. Add a strip of foil over the long exposed ends of the skewers to prevent the skewers from burning.
Place the chicken on the middle rack of the preheated oven and set the timer for 10 minutes. After 10 minutes, turn the skewers over and cook for another 10 minutes.. The chicken should be getting a nice golden color after 20 minutes.
Increase the oven temperature to 500℉.
Baste the chicken with the yakitori sauce and return to the oven for 5 minutes.. After 5 minutes, turn and baste the second side and return for another 5 minutes. The chicken should have a deep golden color and be slightly charred around the edges.