Preheat the oven to 425°F.
Boil noodles al dente according to package directions. Drain.
In a large bowl combine noodles, onions, peas, soup, milk, cheese and tuna. Mix well.
Spread into a greased 9x13 inch baking dish or 2.5 quart casserole dish
Combine the topping ingredients and sprinkle it over the casserole.
Bake for 18-20 minutes or until bubbly.
