Preheat the oven to 400°F and lightly grease a baking dish with non-stick spray.
Make the avocado-Cotija topping: In a small bowl, combine the avocado, crumbled Cotija, dill, and chives.
Squeeze lemon juice over the mixture, then season with salt and pepper to taste. Adjust seasoning if needed. Cover and refrigerate while preparing the salmon.
Prepare the salmon: Pat the fillets dry with a paper towel to remove excess moisture, then place them in the prepared baking dish.
In a separate bowl, whisk together olive oil, lemon juice, lemon zest, and dill. Brush this mixture over the salmon fillets, then season with salt, pepper, and paprika to taste.
Bake the salmon for 10-12 minutes, or until fully cooked and easily flaked with a fork.
Serve immediately, topping each fillet with the avocado-Cotija mixture. Enjoy!