Cook noodles as directed on package, adding peas during last minute of cooking time; drain.
Meanwhile, heat oven to 350°F. In ungreased 2-quart casserole, mix soup, milk, dried onion and seasoned salt.
Stir cooked noodles and tuna into soup mixture. Cover; bake 30 minutes.
Uncover; stir mixture well. Sprinkle with French-fried onions. Bake uncovered about 5 minutes longer or until onions are golden brown.