Trim the scallions, mince the white and light green parts and set aside. Toss the dark green parts into a medium saucepan, add a thin slice of lemon, the wine, water and a pinch of salt and bring to a boil. Drop in the salmon and lower the heat so that the liquid just simmers for a minute (3 minutes if the salmon is frozen), then remove the pan from the heat, cover and set aside for 10 minutes.
Drain the salmon (discard the cooking liquid) and transfer to a plate; refrigerate for 20 minutes. (You can refrigerate the salmon for up to 1 day; cover it once it has cooled).
Using a flexible spatula and working in a medium bowl, beat the butter until it's spreadable. Grate the zest of the lemon over the butter, squeeze the juice from half the lemon into the bowl and add the reserved minced scallions, the shallot, a pinch of salt and a few grinds of pepper. Blend thoroughly, then stir in the smoked salmon.
In another bowl, stir together the mayonnaise, mustard, honey and capers. Squeeze a few drops of lemon juice into the bowl and stir in some pepper. Scrape this out over the smoked salmon mixture and blend well.
Remove the poached salmon from the fridge, cut it into bite-sized pieces and gently stir them into the smoked salmon mixture--even if you're extremely gently, the salmon will flake and flatten; go with it. Fold in the dill and cilantro, then taste for salt, pepper and lemon juice.
You can serve the rillettes now, but the flavor and texture are better if you pack them nto a sealed container and refrigerate for at least 6 hours. Serve with bread or crackers and, if you like, put out with minced herbs that can be sprinkled over each serving.
Notes
The rillettes will keep tightly covered in the fridge for up to 4 days.