Trim the fat off the chicken thighs and season lightly on both sides with salt and pepper. In a small bowl, whisk the sauce ingredients together and set aside.
In a large skillet, add broccoli florets and water. Cover with a lid and cook for 2-3 minutes, or until crisp tender and bright green. Season with salt and pepper and transfer to a bowl. Cover to keep warm.
In the same pan, heat the oil and add the chicken thighs. Sear for about 6-7 minutes on the first side, or until nicely browned. Flip and sear for another 5-6 minutes or until cooked. Whisk the sauce one more time before adding it to the pan. Pour on top of the chicken and let the sauce bubble up to thicken. Toss and coat the chicken in the sauce for 1-2 minutes.
Transfer to a cutting board, let rest for 2 minutes, and then slice thickly. Divide the slices between the two plates and drizzle with remaining sauce left in the pan. Top with sesame seeds and sliced scallions. Serve with rice and steamed broccoli.