Crispy, thinly sliced pieces of hearts of romaine lettuce are combined with sprouts, crispy chow mein noodles and green onions and tossed in a light and simple combination of sesame oil and rice vinegar.
In a small saucepan over medium heat bring the brown sugar, mirin and soy sauce to a boil, stirring until the sugar dissolves. Reduce the heat to low and simmer, stirring occasionally, until the sauce has thickened and reduced, about 30 minutes. Remove from heat and let cool.
The sauce can be made up to 2 weeks ahead of time and refrigerated in an airtight container.
For the teriyaki chicken:
Place the chicken thighs and half of the teriyaki sauce into a large re-salable plastic bag. Refrigerate for at least an hour and up to overnight.
Remove the chicken from the marinade. Heat a large nonstick skillet to medium high. Add the chicken thighs to the pan and cook until completely cooked through, about 4 minutes on each side. Remove and slice the thighs and sprinkle with the sesame seeds.
For the salad:
In a large salad bowl toss together the romaine, chow mein noodles, sprouts, green onion, sesame oil and rice vinegar. Top the salad with the teriyaki chicken and drizzle with 2 tablespoons of the remaining sauce teriyaki sauce.