Marinade the salmon with garlic, oregano, pepper, salt, and lemon juice. Mix well and gradually add lemon zest. Let it sit for 10-15 minutes.
Place the salmon fillets on the grill tray and put them in the smoker. Smoke it for 10-15minutes. Then, flip the sides in between until each gets golden brown.
Now, take a pan and melt butter on medium-low flame. Place smoked salmon fillets on the pan, sprinkle each with chili flakes, and fry for a minute or so.
Serve hot with any side dish you want.