Whisk together maple syrup, soy sauce and garlic in a bowl. Place salmon steaks in a shallow dish and pour the mixture evenly over them. Cover and refrigerate for 30 minutes, rotating salmon once halfway through.
Transfer marinated salmon into the baking dish greased with olive oil (save the marinade). Sprinkle with chives and bake in the oven at 200°C until salmon is cooked through, about 15 minutes.
Meanwhile, pour marinade into a small saucepan, bring to a boil over medium-high heat, stirring frequently. Once it reaches a boil, reduce heat slightly and allow to cook for several minutes, stirring frequently, until reduced to ¼ cup.
Serve salmon warm with 1 Tbs of the maple soy- glaze drizzled over top and black pepper and chives if desired.