1. Season salmon liberally on both sides with smoked sea salt and black pepper and chopped oregano. Place the fish on three layers of foil.
2. Layer with the cherry tomatoes, red onion and jalapeños. Scatter with the remaining oregano leaves. Drizzle with melted butter.
3. Wrap loosely with layered foil. Make a trench in the coals, put a rack in and place the fish on top then carefully put a few coals on top.
4. Cook for 8-10 minutes. Add a grill rack over the top and add the halved limes to the grill and cook cut side down for 4 minutes or until charred.
5. Remove the limes and remove the grill. Move the coals aside and remove the salmon to a baking tray to rest in the unopened foil parcel for 5 minutes.
6. Open the parcel, move the salmon to a serving platter with fish spatulas.
7. Squeeze over charred lime juice and serve.