For the marinade: To a medium bowl add 2 tablespoons oil, lime juice, cumin, granulated garlic, Mexican oregano, chili powder, paprika, crushed red pepper flakes, and seasoned salt. I used Crazy Mixed Up Salt. Mix well with a fork and set aside.
For the chicken: I used one pound of boneless, skinless chicken breast, partially thawed. You can get thinner slices if the meat is a bit on the frozen side. slice the chicken breast into thin slices and place in the bowl with the marinade. The marinade is more of a paste so get in there with your hands and make sure every bit of chicken is coated. Cover the bowl and refrigerate at least one hour, but not more than four hours.
For the vegetables: Slice the bell pepper and white onion into half-inch slices. Slice the green tops of the scallions into thin 2 inch-long strips. Save the whites for another dish.
Cooking the vegetables: Heat a grill pan to hot. Pour the remaining 2 tablespoons oil onto the pan and brush the pan evenly with a heat-proof brush. Place the onion and peppers on the hot grill pan. Use tongs to move the vegetables around on the grill pan until lightly charred. Do not over cook the vegetables! You want some crispness left. Just before removing the vegetables from the pan add the scallion tops and toss for a minute. Remove the vegetables from the pan and set aside. Leave any remaining oil on the grill pan.
Cooking the chicken: Pour off and discard any marinade remaining in the bowl. Use tongs to place the chicken strips onto the hot grill pan. Grill the chicken in two batches so that it chars and does not steam from overcrowding in the pan. Add the first batch to the vegetables and cook the next batch of chicken. Allow the chicken to sit on the grill for enough time to get grill marks then toss and continue to cook for 5 minutes. There should be no pink left in the center of the strips.
Finishing the fajitas: When the second batch of chicken is done, add the first batch and the vegetables to the grill pan and toss until heated through. In a seagate frying pan, brush oil in a thin layer and grill the flour tortillas until soft with bits of brown. Wrap in foil and place in a 250 degree oven to keep warm.
Serving the fajitas: Place the fajita mixture onto a warm tortilla. Top with guacamole, pico de gallo, sour cream, Oaxaca cheese, and cilantro. Squeeze a lime wedge over the top and sprinkle lightly with Cotija cheese. Enjoy!