1. Preheat oven to 350 degrees and grease on 12x9x2 inch baking pan.
2. In a saucepan mix rice, salt, and 3 cups of water and bring to a boil.
3. Cover and simmer for 15 minutes. Remove saucepan from heat and set aside for additional 15 minutes.
4. Saute onions in margarine (or butter) until tender.
5. Mix soup, milk, 1/2 cup of water, onions, and rice. Spoon mixture into baking pan.
6. Thaw and drain the vegetables and then spread over the rice mixture.
7. Spread the cheese evenly over the top and bake at 350 degrees for 25-30 minutes until cheese is melted and rice is bubbly.