Season beef with a teaspoon of salt, a pinch of black pepper, thyme, and oregano. In a large cast aluminum or cast iron pot, heat half the oil. Sear the meat throughout (be careful with splatters, you are trying to cook the beef, not yourself).Add enough water to cover the meat and cover the pot with a tight-fitting lid. Simmer over low heat until the meat is very tender (it will start to flake). Rotate the meat every once in a while so it cooks uniformly. Add water if it becomes necessary so it doesn't get completely dry. By the end, you should have left about 3 cups of liquid. Cool down to room temperature
Shredd meat
Once the meat is cool enough to handle, cut into slices no more than 2 inches wide and shred the meat with your hands.
Make sauce
In a heavy saucepan heat the remaining oil and cook and stir the onions until they become translucent. Add the garlic, carrots and peppers and simmer over very low heat for 3 minutes. Add the tomatoes and simmer for about 10 minutes until the tomatoes are tender.
Simmer meat
Add the vinegar and tomato sauce and the meat and the remaining liquid from boiling the meat.Simmer for 10 minutes over low heat, or until all the vegetables are cooked through. Taste and season with salt to taste if needed.