Cook the rice using chicken stock according to the package directions. Wait to heat the pan for the stir-fry until the rice is 10 minutes from being ready to eat.
Cut the meat lengthwise into 2 thin steaks, then wrap in plastic wrap and place in the freezer for 10 minutes to firm it up for thin slicing.
Toast the cumin and peppercorns in small skillet then grind in a spice mill.
Very thinly slice the meat on an angle, against the grain into bite-size pieces.
Heat a large skillet over high heat with the stir-fry oil. When the oil ripples and smokes, add the meat and cook until browned. Remove the meat and add the garlic, chiles, peppers, cinnamon, ginger, mushrooms, onions and toasted spices. Stir-fry until tender-crisp, 2 to 3 minutes. Add the sherry. Add the scallions to the skillet with the beef, then toss with the soy sauce and cilantro. Serve with rice.
*You can find the small dried whole red chiles in pouches in the Asian food section of your market or with the dried peppers in the produce section.