Heat the oil in an wide skillet. Sauté the onion over medium heat until translucent. Add the bell pepper and continue to sauté until lightly golden.
Add the tofu, tortillas, tomatoes, salsa, chilies, and cumin. Stir together gently. Cover and cook over medium heat for 10 minutes, or until everything is piping hot and nicely melded together.
Season with salt and pepper. If using vegan cheese, sprinkle it over the top, then cook, covered for another 2 to 3 minutes, or until it has melted.
Garnish with cilantro or parsley if you'd like, and serve straight from the pan.