Preheat your oven to 400°F and line a large rimmed baking sheet with parchment paper.
Cut the eggplant into uniform 1-inch cubes and place them in a medium mixing bowl.
Toss the eggplant cubes with 1 teaspoon of olive oil, garlic powder, dried oregano, and half of the sea salt and black pepper.
Spread the eggplant in a single layer on the prepared baking sheet and roast for 20-25 minutes, tossing halfway through, until tender and golden brown.
While the eggplant roasts, pat the salmon fillet completely dry with a paper towel on all sides to ensure a crisp sear.
Season the salmon fillet evenly with the remaining sea salt and black pepper.
Heat the remaining 1 teaspoon of olive oil in a high-quality non-stick or cast-iron skillet over medium-high heat until shimmering.
Place the salmon in the pan, skin-side down, and press gently with a spatula for 10 seconds to prevent curling.
Sear the salmon undisturbed for 4-5 minutes until the skin is crispy, then carefully flip and cook for another 2-3 minutes until the flesh is opaque.
Remove the skillet from the heat, drizzle the salmon with fresh lemon juice, and serve immediately alongside the roasted eggplant.