Heat the oven: Preheat to 400°F (200°C).
Line a baking sheet with parchment for easy cleanup.
Prep the salmon: Pat the fillets dry with paper towels. Dry surfaces help you get better browning and less steaming.
Make the seasoning: In a small bowl, combine 2 tablespoons olive oil, lime zest, minced garlic, chili powder or paprika, cumin, 3/4 teaspoon salt, and 1/4 teaspoon black pepper. Stir into a paste.
Season the fish: Brush or rub the paste over the top and sides of the salmon.
Place fillets on the prepared sheet, skin-side down if using skin-on.
Bake: Cook for 10–14 minutes, depending on thickness. Salmon is done when it flakes easily and the center is just opaque. For many fillets, 12 minutes is the sweet spot.
Make the avocado salsa: While the salmon bakes, combine the diced avocados, cherry tomatoes, red onion, jalapeño, and cilantro in a bowl.
Add 1–2 tablespoons lime juice, 1 tablespoon extra-virgin olive oil, and a pinch each of salt and pepper. Toss gently to avoid mashing the avocado.
Taste and adjust: Add more lime for brightness, more salt if it tastes flat, or extra jalapeño for heat. The salsa should be punchy and fresh.
Rest the salmon: Let the salmon rest for 2–3 minutes after baking so the juices settle.
Serve: Spoon the avocado salsa over the warm salmon.
Finish with an extra squeeze of lime, if you like.