Bring a large pot of lightly salted water to a boil. Add 1 tablespoon oil to the water to prevent sticking. Add pasta and cook for 8 to 10 minutes or until al dente; drain. Preheat oven to 350 degrees F (175 degrees C).
In a 2 quart saucepan over medium heat, combine the cream of mushroom soup, mixed vegetables, canned tuna, and 1 cup of the cheddar cheese. Gently fold pasta into the soup mixture and mix thoroughly. Pour pasta and soup mixture into a 11x7 inch baking dish. Sprinkle remaining cup of cheese on top.
Bake in a preheated oven until cheese is melted and bubbly.