In a large saute pan, over medium heat, heat the oil. Add the onions. Season with salt and pepper, and cook, stirring. Saute until the onions are slightly soft, about 3 minutes. Add the water and garlic. Bring the mixture to a boil, reduce the heat to medium, and simmer for about 6 minutes. Add the rice and simmer for 10 minutes, stirring constantly. Add the tomatoes and continue to simmer, stirring constantly, until the mixture is creamy and bubbly, about 8 minutes. Stir in the butter, cream, cheese and green onions. Simmer for 2 minutes, stirring constantly. Remove from the heat. Spoon the risotto into serving bowls or plates and serve.