Prepare rice according to packaging instructions. Usually one part rice to two parts water, simmer for 20 minutes or until water is absorbed.
While the rice is cooking, dice the tomatoes, onions, garlic and mushrooms but keep separate. Don't be afraid to try other veggies too.
Add the olive oil to a large sauce pan over medium flame. Begin sautéing the onions and garlic. When the onions start to brown a little and get soft, add the mushrooms and finally the tomatoes a few minutes later.
Once the tomatoes have cooked down a bit, add the vegetable stock (or water), vinegar and spices. Add the salt gradually while it cooks so as to not over do it. It's better to need to add salt to your serving that it is to make it too salty! Let the entire mixture cook down until the vegetable stock is more of a soupy texture. It shouldn't take too long. You want it to be almost like salsa in texture. Once again, don't over do it. It's better for it to be too soupy and need additional cooking than to dry it out!
By the time you are satisfied with it, your rice should be finished. Fold it into the vegetables and stock scoop by scoop. Allow the rice to simmer into the vegetables for a minute or two and then serve. Great for a quick but healthy lunch and you can make it when there isn't much else around the kitchen because it doesn't need anything special.
Another option you might try is replacing the rice with macaroni or some other pasta.