Place steaks in single layer in freezer bag. Whisk 1/4 cup teriyaki sauce, the vinegar, 1/2 cup scallions, garlic, ginger and pepper flakes in small bowl. Pour into freezer bag with steak; turn to coat. Let marinate for 1 hour, or refrigerate overnight.

To freeze, place bag with steaks in freezer. Night before serving, transfer bag to refrigerator to thaw the steaks.

Heat broiler. Remove steaks to broiler-pan rack. Pour marinade into small saucepan.

Broil meat 6 inches from heat for 8 to 10 minutes. Turn meat over. Broil 4 to 5 minutes or until instant-read thermometer inserted in thickest part registers 140 degrees F for medium-rare. Remove meat to cutting board. Let rest for 5 minutes.

Meanwhile, bring large pot of water to boiling. Gradually add spaghetti; boil for 6 minutes. Add green beans; boil for another 4 minutes or until beans and spaghetti are tender. Drain beans and spaghetti; transfer to serving bowl. Slice beef; add to spaghetti and beans in bowl and toss to mix.

Whisk remaining teriyaki sauce, the cornstarch, sesame oil and sugar into marinade in saucepan. Bring to boiling; boil, stirring occasionally, 2 to 3 minutes or until thickened. Pour over beef and noodle mixture; toss well to combine. Sprinkle with remaining 1/4 cup chopped scallions. Makes 6 servings.