Preheat & Prep: Adjust an oven rack to the middle position and preheat to 425°F (220°C). Cut the salmon into uniform 1-inch cubes.
Combine Seasonings: In the small bowl, stir together the smoked paprika, kosher salt, and garlic powder until well combined.
Coat the Salmon: Place the salmon cubes in the large mixing bowl. Drizzle with the avocado oil and toss gently to coat. Sprinkle the seasoning blend over the salmon and toss again until every piece is evenly covered.
Achieve the Initial Sear: Place the cast-iron skillet over medium-high heat. Once hot, carefully arrange the salmon cubes in a single layer, ensuring they don’t touch. Cook for 2–3 minutes without moving them to develop a deep, flavorful crust on one side.
Finish in the Oven: Place the entire skillet into the preheated oven. Roast until the salmon is cooked through and flakes easily with a fork, about 4–6 minutes. The internal temperature should register 145°F (63°C) on an instant-read thermometer.
Garnish and Serve: Carefully remove the skillet from the oven. Squeeze the fresh lime wedges over the hot salmon. Transfer the cubes to a serving platter and garnish generously with the fresh dill, minced shallot, and lime zest. Serve immediately.