In a small bowl, combine chili powder, ground cumin, smoked paprika, cayenne pepper, salt, and black pepper. Mix well to create the fajita seasoning.
Heat olive oil in a large skillet over medium-high heat.
Add the sliced bell peppers and onion to the skillet. Cook, stirring occasionally, until the vegetables are tender-crisp, about 5 minutes.
Add the minced garlic and cook for 1 minute until fragrant.
Push the vegetables to the side of the skillet and add the shrimp in a single layer.
Sprinkle the fajita seasoning evenly over the shrimp and vegetables.
Cook the shrimp for 2-3 minutes on each side until they turn pink and are cooked through, stirring the vegetables occasionally to combine flavors.
Remove the skillet from heat and drizzle fresh lime juice over the shrimp and vegetables.
Sprinkle chopped fresh cilantro on top and gently toss everything together.
Serve the shrimp fajita skillet hot with warm tortillas or over rice if desired.