Bring a large pot of water to boil. In the mean time, cut off the tops of peppers about half an inch from the stem and remove the seeds. Do not throw out the tops. Remove stem finely dice the flesh. Add a little salt to boiling water and completely submerge peppers with thongs. Cook peppers for about 2 minutes. Remove and allow to cool.
Heat olive oil in a medium sized pot. Add garlic, peppers, and thyme. Sauté for about 2 minutes. Stir in rice and tomatoes.
Add water or vegetable broth. Bring to a boil. Season with salt and pepper. Reduce heat to medium low, cover and allow to simmer for about 35 to 40 minutes or until all water is absorbed. Turn off heat and let stand for 10 minutes.
Fluff rice and spoon into prepared peppers.
Place on a baking dish and bake in 350°F oven for 40 minutes. Remove and garnish with green onions. Serve immediately.