Step 1: In a small bowl, combine the chili powder, smoked paprika, cumin, garlic powder, onion powder, salt, and black pepper to create the fajita seasoning.
Step 2: In a large bowl, toss the shrimp with 1 tablespoon of olive oil and half of the seasoning mixture until well coated.
Step 3: In another bowl, toss the sliced bell peppers and onions with the remaining tablespoon of olive oil and the rest of the seasoning.
Step 4: Heat a large skillet or cast-iron pan over medium-high heat. Add the vegetables and cook for 5-6 minutes, stirring occasionally, until they are slightly softened and charred.
Step 5: Remove the vegetables from the pan and set them aside on a plate. Add the shrimp to the same hot skillet in a single layer.
Step 6: Cook the shrimp for 2 minutes per side until they are pink and opaque. Do not overcook.
Step 7: Return the vegetables to the pan, pour the fresh lime juice over the mixture, and toss everything together for 1 minute to reheat.
Step 8: Serve immediately with warm tortillas and your choice of toppings like avocado, sour cream, or extra lime wedges.