Mix salt with flour and add the eggs until you get thick paste. Then pour in cold milk slowly while whisking, to prevent formation of lumps. Add melted butter and let rest 1 hour.
Heat a non-stick pan and brush with melted butter, pour enough batter to coat the bottom of the pan and cook on medium heat until brown, 2 to 3 minutes, flip around and cook 1 or 2 minutes more.
Bring the wine to a boil with salt, pepper, tarragon stems and some butter. Place the salmon in it and cook until it starts to fall apart and the white albumen of the fish starts to appear. Remove fish, crumble it. Add fresh tomatoes or already made tomato sauce to the cooking liquid, reduce until in coats the back of a spoon nicely. Add the chopped tarragon leaves at the end. Place the fish back in the sauce and fill each crepe with a small amount of filling and roll. Place each crepe on a plate and cover with 2 or 3 tablespoons of left over salmon filling. Garnish with chopped hard-boiled eggs.