Heat oven to 425°F. Coat 13 x 9-inch baking dish with nonstick cooking spray.
Bring large pot of salted water to a boil. Cook pasta following package directions. Drain; return to pot. Stir in tomatoes and chopped onions.
Cook spinach in microwave following package directions. Squeeze out moisture. Transfer to a bowl. Add Alfredo sauce, ricotta, garlic salt and pepper; stir to combine.
Transfer spinach mixture to pasta pot; toss to combine. Transfer pasta mixture to prepared baking dish.
Mix together bread crumbs, Parmesan and oil. Sprinkle over pasta. Bake at 425°F for 20 to 25 minutes or until golden brown and bubbly.