In a small bowl whisk all the marinade ingredients. Place the steaks in a large, resealable plastic bag and pour in the marinade. Press the air out of the bag and seal tightly. Turn the bag to distribute the marinade, place in a bowl and marinate at room temperature for 1 hour or refrigerate for up to 24 hours, turning occasionally.
In a small bowl whisk all the sauce ingredients.
Prepare the grill for direct cooking over medium heat (350° to 400°F). Preheat a cast-iron skillet or griddle for 10 minutes.
Prepare the grill for cooking over medium heat (400°F). Preheat a cast-iron skillet or griddle for 10 minutes.
Add the oil to the skillet. Add the mushrooms and cook over direct medium heat, with the lid closed, until softened and beginning to color, 8 to 10 minutes, turning as needed. Remove from the heat and season with salt.
Add the oil to the skillet. Add the mushrooms and cook over medium heat, with the lid closed, until softened and beginning to color, 8 to 10 minutes, turning as needed. Remove from the heat and season with salt.
Raise the heat of the grill to direct cooking over high heat (500° to 550°F).
Raise the heat of the grill to high heat (550°F).
Remove the steaks from the bag and discard the marinade. Grill the steaks over direct high heat, with the lid closed, until an instant-read thermometer inserted into the center of the steaks registers 125°F (or your preferred doneness), 7 to 9 minutes for medium rare, turning once or twice. Remove from the grill, and rest the steaks at room temperature, indoors, for 3 to 5 minutes. Cut the steaks against the grain into thin slices.
Remove the steaks from the bag and discard the marinade. Grill the steaks over high heat, with the lid closed, until the center of the steaks registers 125°F (or your preferred doneness), 7 to 9 minutes for medium rare, turning once or twice. Remove from the grill, and rest the steaks at room temperature, indoors, for 3 to 5 minutes. Cut the steaks against the grain into thin slices.
Divide the rice between bowls. Arrange the steak, mushrooms, carrots, and scallions around the bowl. Drizzle with some of the sauce. Garnish with the cilantro and sesame seeds. Serve with the remaining sauce for passing.