Place the salmon on parchment paper and grill at 100 °C for 15–20 minutes. Adjust the time based on the thickness of the salmon. The goal is to cook the salmon through without browning it like a typical grilled fillet.
Once cooked, let the salmon cool. Flake it gently once it is cool enough to handle. You may notice some white substance on the surface (albumin, a common salmon protein) – scrape it off with a spoon. Discard any brown flesh if present.
Chop the smoked salmon into small pieces and set aside.
In a pan over low heat, melt the butter and sauté the chopped shallots until translucent. Remove from heat and let cool.
In a bowl, mix together the flaked salmon, chopped smoked salmon, cooled shallots, chives, Japanese mayonnaise, Crème fraîche, black pepper, and smoked paprika until well combined.
Transfer the mixture into a jar and press down with a spoon to eliminate gaps. Cover the surface firmly with cling wrap and refrigerate for at least 2 hours to allow the flavours to meld.
Serve with toast or crackers.