In a large skillet, melt butter and sugar over medium heat. Add the noodles, sesame seeds and almonds. (Discard seasoning packets from noodles or save for another use.) Cook and stir for 6-8 minutes or until browned; set aside. In a large salad bowl, toss the romaine and onions.
In a jar with a tight-fitting lid, combine the dressing ingredients; shake well. Just before serving, drizzle over romaine mixture; top with noodle mixture. Toss to coat.