Steam asparagus and 8 scallions in a steam basket over boiling water (or in the microwave, with a small amount of water) until crisp-tender, about 5 minutes. Rinse with cold water to stop the cooking and set color. Drain and cool.
To make the dressing, heat oil in a small saucepan over medium-high heat. Add ginger and stir until it begins to color. Add half the minced scallions and cook a few seconds. Add broth, vinegar, soy sauce and sugar. Set aside.
Just before serving, place the remaining minced scallions in a large bowl. Add steamed asparagus and scallions. Bring the dressing to a boil over medium-high heat. Let boil 30 seconds Gradually stir in pepper and lemon juice, tasting to achieve an appealing tart and peppery flavor. Toss the vegetables with the dressing.