Slice the skirt steak against the grain into thin strips.
In a small bowl, whisk together the cumin, smoked paprika, garlic powder, sea salt, and black pepper.
Toss the steak strips with the spice blend until every piece is thoroughly coated.
Heat the olive oil in a large cast-iron skillet over medium-high heat until it begins to shimmer.
Add the steak to the skillet in a single layer and sear for 2-3 minutes until a dark, caramelized crust forms.
Remove the steak from the pan and add the sliced bell peppers and onions to the remaining juices.
Sauté the vegetables for 4-5 minutes until they are tender and show slight charred edges.
Return the steak to the skillet, toss with the vegetables, and squeeze the fresh lime juice over the top.
Warm the corn tortillas in a dry pan for 30 seconds per side until pliable.
Serve the steak and pepper mixture inside the warm tortillas and garnish with fresh cilantro.