In a small bowl, combine kosher salt, black pepper, chili powder, garlic powder, onion powder, ground cumin, and smoked paprika. Mix well until evenly blended. Set aside.

Heat 1 tablespoon olive oil in the skillet over high heat. Once shimmering, add red onion, yellow bell pepper, red bell pepper, and orange bell pepper. Sprinkle half the seasoning over vegetables and sauté for about 5 minutes until softened and slightly charred.

Push vegetables to the side, add another tablespoon of olive oil, and then add shrimp. Sprinkle remaining seasoning on the shrimp and stir everything together. Sauté for 3-5 minutes until shrimp are pink and opaque.

Remove skillet from heat and squeeze lime juice over the mixture. Toss gently to coat the fajitas in lime juice.

Warm tortillas in a separate skillet or microwave. Spoon shrimp and vegetable mixture onto tortillas, allowing customization, and add cilantro if desired. Serve immediately.