Position a rack in the middle of the oven. Preheat oven to 375°F | 190°C. Line a baking tray / sheet with a large piece of foil, big enough to fold over and seal to create a packet (or 2 long pieces of foil over lapping each other lengthways to create your salmon packet, depending on the width of you fillet).

In a small saucepan, combine the honey, soy sauce and butter over low-medium heat, and whisk until the honey has melted through the butter and the mixture is well combined. Take off the heat, and add in the lemon juice, garlic, vinegar, Sriracha, sesame oil, ginger, sesame seeds and chili flakes. Transfer 1/4 cup of sauce into a small dish for serving later; set it aside.

Place the salmon onto prepared baking tray | sheet and season with salt (about 1 teaspoon -- adjust to your taste). Pour the honey sesame mixture (from the pan) over the salmon, and spread evenly with the back of a spoon or spatula to evenly cover in sauce.

Fold the sides of the foil over the salmon to cover and completely seal the packet closed to prevent the sauce from leaking.

Bake until cooked through (about 12-15 minutes, depending on the thickness of your fish and your preference of doneness). Open the foil, being careful of any escaping steam, and grill / broil under the grill / broiler for 3-5 minutes on medium heat to caramelise the top (keep your eye on it so it doesn't burn). Pour the reserved sauce over the salmon and garnish with green onion slices. Serve immediately with lemon wedges.