Preheat the oven to 230 degrees C. Grease two large pieces of aluminum foil with vegetable oil.
Place the salmon filet on top of one piece of foil. Sprinkle salmon with salt, pepper, garlic and chopped dill. Arrange the lemon slices on top of the fillet and lay a sprig of dill on top of each lemon slice. Sprinkle the fillet with chopped green onions.
Cover the salmon with a second piece of foil and tightly clamp the ends. Place on a baking sheet. Bake in a preheated oven for 20 to 25 minutes.