Whisk together the Orange Juice, Lime Juice, minced Garlic, finely chopped Jalapeño (seeded if you prefer less heat), chopped Cilantro, Ground Cumin, Mexican Oregano, Kosher Salt and Black Pepper with a tablespoon or two of Neutral Oil to make a bright, well-seasoned marinade.
Place the Skirt Steak in a shallow dish or resealable bag and pour the marinade over it, turning to coat. Refrigerate for at least 30 minutes and up to 4 hours for best flavor—avoid much longer to prevent the citrus from over-tenderizing the meat.
About 20–30 minutes before cooking, remove the steak from the fridge and let it come toward room temperature while you preheat a grill or heavy skillet to high heat.
Oil the grill grates or skillet lightly with neutral oil and sear the steak 3–5 minutes per side (depending on thickness) until nicely charred on the outside and cooked to your preferred doneness; aim for about 125–130°F for medium-rare.
Transfer the steak to a cutting board and let it rest for 8–10 minutes so the juices redistribute.
While the steak rests, warm the Corn Tortilla on the hot grill or skillet for 20–30 seconds per side until pliable and lightly charred. Keep them covered with a clean towel to stay warm.
Thinly slice the steak against the grain into bite-sized strips, and chop the White Onion and additional cilantro to taste.
To assemble, place slices of steak on each warmed tortilla, top with chopped onion and cilantro, spoon over some Salsa Roja, and finish with a squeeze of Lime.
Serve immediately with extra jalapeño slices or lime wedges on the side for added heat and brightness.
