Preheat oven to 400°F. Line a rimmed baking sheet with parchment for easy cleanup.
Pat salmon dry and place skin-side down on the sheet. Drizzle with olive oil and rub with minced garlic, chili powder, cumin, 0.75 tsp salt, and black pepper.
Bake until the salmon is just opaque and flakes easily with a fork, 10 to 12 minutes depending on thickness.
While the salmon bakes, combine avocado, red onion, cherry tomatoes, cilantro, lime juice, and the remaining 0.25 tsp salt in a bowl. Gently toss to coat.
Rest salmon for 3 minutes. Spoon avocado mixture over the fillets and serve with lime wedges.
Notes
For extra richness, finish the salmon with a light drizzle of olive oil or a pinch of flaky sea salt. If using farmed salmon, reduce bake time slightly; thicker wild fillets may need a minute more.