Heat olive oil over medium high heat in a large pan. Add in chicken, and season with a bit of salt, pepper and cumin. Cook until chicken is browned, about 4 minutes on each side.
Add in garlic and cook for a minute. Then add in peppers and onions, and cook for another 4 minutes.
Now stir in the soy sauce and vinegar, and cook for another 3-4 minutes.
Add in the cilantro and tomatoes, and cook for another 2-3 minutes. Serve immediately.