Preheat the oven to 400°F (200°C). Line a baking sheet with parchment paper for easy cleanup.
In a small bowl, mix the olive oil, garlic powder, onion powder, paprika, oregano, cayenne, salt, and pepper to form a spice rub.
Pat the salmon fillets dry with paper towels. Place them on the prepared baking sheet.
Brush or rub the spice mixture evenly over each fillet.
Squeeze fresh lemon juice over the top of the salmon.
Bake for 12 to 15 minutes, or until the salmon flakes easily with a fork and is opaque in the center.
Let the salmon rest for a few minutes before serving.
Garnish with chopped parsley and serve with lemon slices.