Spray an 18"x 13" pan. Preheat the oven to 400F degrees. Thinly slice the flank steak (cutting across the grain).
Place sliced steak in a medium bowl and drizzle 1 Tablespoon of olive oil over and set aside.
Put the sliced bell peppers and onion into a separate medium bowl and drizzle with the remaining 1 Tablespoon of olive oil and set aside.
Mix together the salt, pepper, cumin, chili powder, and garlic in a small bowl.
Stir in half of the seasoning mixture into the vegetables.
Stir in the other half of the seasoning mixture into the sliced steak.
Sprinkle the lime juice over all (½ over meat, ½ over vegetables).
Place the vegetables in a single layer onto the baking sheet. Bake on the upper rack of the oven for about 10 minutes (the vegetables should just be starting to get soft.)
Move the vegetables over to make room for the steak. Then add the steak in a single layer to the baking pan.
Bake on the upper rack for about 5 minutes or until the steak is cooked the way you like. Keep a close eye on the steak to make sure it is cooked to your preference.
Serve in warmed tortillas with your favorite toppings.
Notes
Nutritional value does not include toppings.
These can be frozen, see my tips above.
Make sure that you do not cook everything at once otherwise the steak will be overcooked.
You can substitute the individual spices in this recipe with a packet of taco seasoning or fajita seasoning.
Two smaller baking pans can be used if you don't have one large pan.