Place sesame seeds in a small skillet and set pan over medium-low heat. Cook 1 to 3 minutes, until just golden brown, shaking the pan frequently to prevent burning. Remove from heat and set aside.
Place lettuce in a large bowl (or divide onto individual dishes). Top lettuce with beef, carrots, scallions and cilantro.
In a small bowl, whisk together broth, vinegar and sesame oil. Season with salt and pepper, to taste. Pour mixture over salad, and top with toasted sesame seeds. Serve immediately.