Season the flank steak with 1 tbs of salt and 1 ½ tbs of garlic powder on each side. Cut the flank steak into four rectangular/square pieces. Place the steak in a pressure cooker along with ½ an onion, ½ green pepper, and 4 garlic cloves. Add 4 cups of water (this should be enough water to cover the meat). Cook under pressure for 10 minutes.
While your flank steak is cooking, squeeze in 1/3 cup of orange, lemon, and lime juice. Stir together. Add the cumin, oregano, and black pepper and mix to combine. Also, at this time, cut the remaining onions into strips and mince the remaining garlic cloves.
Once the flank steak is done cooking, remove from the pressure cooker and shred into pieces using two forks.
Heat 6 tbs of oil over medium-high heat. Once hot, add the shredded flank steak and half of the onions and all the garlic. Stir to coat with oil and let it cook for five minutes. After five minutes add about 1/3 of the citrus and seasoning mixture and stir. Let it cook for another five minutes without stirring so that the steak starts to become crispy. After these five minutes, add the remaining onions and another 1/3 of the citrus and seasoning mixture and stir to combine. Allow to cook for another five minutes and add the remaining citrus and seasoning mixture. Cook for another five minutes. Each time you mix the steak, you should notice that the steak in the bottom is becoming crispy.