Wash watercress (or spinach) in colander. Pour boiling water over watercress. Immediately plunge vegetable into cold water to stop cooking process; drain and reserve. You can refrigerate or use at room temperature. Cream sesame paste, bean cheese and salad oil. Add chili flakes, sugar, lemon juice and cold water; mix well. Shortly before serving, toss dressing with watercress. Serve on individual salad plates.