In a large skillet over medium-high heat, add the sesame oil and heat. Add the cabbage and carrots and saute for 2 minutes. Add the beef and cook, stirring, until the beef is heated and the cabbage begins to wilt, about 2 minutes. Add the hoisin sauce and soy sauce and cook 5 minutes, until mixture heats through and cabbage wilts, stirring frequently.
Meanwhile, bring the water to a boil. Place the couscous in a heatproof bowl and sprinkle with salt, pepper, and curry powder. Pour the boiling water over the couscous and cover for 5 minutes. Fluff with a fork.
Spoon some of the beef into the center of each lettuce leaf and roll up. Serve with the couscous.