Drain & Flake the Tuna and set it aside for later. Cook the noodles according to the manufacturers instructions then drain & rinse in hot water. Combine the noodles with the tuna, celery, and green onions. Blend in the sour cream, mustard, miracle whip, thyme and salt. spoon half of the mixture into a buttered 2 litre casserole dish. top with half the zucchini, then add the rest of the mixture, and again,m add remainder of zucchini. Cover the dish. Microwave at high power for 6-8 minutes. Top the dish with the cheese and tomato. Microwave at high power for 2 more minutes, and let stand for 3 minutes before serving. Notes: Microwaves range in times required for cooking because of the wattage they use. the one I use is a 1000 watt Sanyo oven. This dish is approx. 400 calories & 24 grams carbohydrates per serving.