Step 1: Marinate the Steak

1. Prepare the marinade: In a small bowl, mix together olive oil, lime juice, chili powder, smoked paprika, ground cumin, garlic powder, onion powder, salt, and black pepper.
2. Marinate the steak: Place the steak in a shallow dish or zip-top bag, then pour the marinade over it. Ensure the steak is evenly coated. Let it marinate for at least 30 minutes at room temperature or up to 4 hours in the refrigerator.

Step 2: Cook the Steak

1. Preheat the skillet or grill: Heat a cast-iron skillet or grill pan over medium-high heat. Add a splash of olive oil if using a skillet.
2. Cook the steak: Remove the steak from the marinade and cook it for about 3-4 minutes per side for medium-rare (adjust time based on desired doneness). Let the steak rest for 5 minutes before slicing.
3. Slice the steak: Cut the steak into thin strips or bite-sized pieces, cutting against the grain to ensure tenderness.

Step 3: Prepare the Vegetables (Optional)

1. Sauté the vegetables: If using bell peppers and onions, heat a skillet over medium heat with a splash of olive oil. Add sliced peppers and onions, then season with a pinch of salt and pepper. Cook for 5-7 minutes, stirring occasionally, until softened and slightly caramelized.

Step 4: Assemble the Quesadilla

1. Prepare the tortilla: Place one tortilla on a flat surface or plate. Sprinkle a layer of shredded cheese over half of the tortilla.
2. Add the fillings: Top the cheese with sliced steak and any optional fillings, such as sautéed vegetables. Add another layer of cheese on top for extra gooeyness.
3. Fold the tortilla: Fold the tortilla in half to create a semi-circle. Press down gently to hold the filling in place.

Step 5: Cook the Quesadilla

1. Heat the skillet: Heat a large skillet over medium heat and add a small amount of olive oil or butter to coat the pan.
2. Cook the quesadilla: Place the folded quesadilla in the skillet. Cook for 2-3 minutes on one side, pressing down gently with a spatula to ensure even browning and melting. Flip the quesadilla and cook for another 2-3 minutes until the tortilla is golden and crispy and the cheese is fully melted.
3. Repeat: Repeat the process with the remaining tortillas and fillings.

Step 6: Slice and Serve

1. Slice the quesadillas: Use a sharp knife or pizza cutter to cut each quesadilla into 3-4 wedges.
2. Serve: Arrange the wedges on a platter and serve immediately with your favorite toppings and dips, such as guacamole, sour cream, and salsa.