Whisk together the tahini, soy sauce, honey, garlic, sesame oil, crushed red pepper, and black pepper in a small bowl. Set aside.
In a large pot of salted boiling water, blanch the brussels sprouts for 30 seconds. Drain and set aside.
In a large skillet, heat 2 tablespoons olive oil. Add the chicken and stir-fry over moderately high heat until no longer pink and cooked through, about 5 to 7 minutes. Transfer to a plate.
Heat the remaining 2 tablespoons oil in the skillet. Add the brussels sprouts and cook over moderately high heat until they start to turn soft, about 6 to 8 minutes.
Stir the tahini sauce into brussels sprouts and then add the chicken and cook until warmed through, 1 to 2 minutes. Season with additional soy sauce if desired. Serve with rice.
