In a medium bowl, whisk together soy sauce, lime juice, orange juice, canola oil, brown sugar, minced garlic, fajita seasoning, jalapenos, cumin and black pepper. Season to taste with salt.
Pour ½ cup marinade in a large bowl or a gallon-size zip-loc bag; set aside.
Transfer the cut steaks to a gallon-sized zip-loc bag and pour the marinade over the steak. Squeeze out excess air from the bag and seal. Massage the marinade over the meat until all the meat is fully coated. Transfer the meat (in the bato a pan large enough for it to lay flat and place it in the fridge. Refrigerate 2-10 hours, flipping the bag over often.
When ready to cook, remove the meat from the fridge 15-30 minutes before using. Before cooking the meat, wipe off the excess marinade with paper towels.
While the meat marinates, add the cut vegetables to the reserved ½ cup marinade and toss to coat. Refrigerate until ready to use, stirring occasionally.