1. Brush manicotti with oil and then cover with half the water needed for boiling. Cover with plastic wrap. Cook manicotti in 13x8x2 dish on High for 22-25 minutes, turning over with a fork every 5 minutes.
2. Dice cheese into ½ inch chunks before separating slices. Reserve about 1/3 cup for topping. Combine rest of mozzarella with ricotta, romano, spinach, garlic, salt, and pepper. Stuff cooked manicotti with cheese filling. Arrange in greased 13x8x2 inch dish.
3. Mix tomatos, marjoram, Italian Seasoning, garlic salt and pepper. Pour sauce mixture over top of manicotti. Sprinkle with cheese. Cover with wax paper. Microwave at high power for 15-18 minutes. Rotate dish halfway through cooking.