Preheat your oven to broil. Line a rimmed baking sheet with aluminum foil and spray with cooking spray.
In a small bowl, mix together the chili powder, paprika, sugar, and salt.
Generously sprinkle the chili powder mixture evenly over the tops of the salmon fillets.
Place the salmon on the prepared baking sheet and broil for 6-9 minutes, depending on how thick your fillets are and how crispy you prefer the crust.
Remove the salmon from the oven and brush the maple syrup over the tops to coat the spice rub. Return to the oven and broil for an additional 1-2 minutes until the maple syrup is bubbling and has formed a crust. Serve immediately.