Step 1Place the salmon fillet on a plate. Run your finger over the salmon and pull out any bones with the aid of tweezers or a paring knife.
Step 2In a very small bowl or cup, combine 3 tablespoons olive oil, 1 tablespoon wine, the paprika, one-eighth teaspoon salt and a pinch of pepper and whisk until the mixture is blended. Stir in 2 teaspoons dill. Spoon the mixture evenly over the salmon. Rub it lightly into the fish and let it stand for 10 to 15 minutes.
Step 3Heat the oven to 450 degrees. Line a roasting pan with foil and lightly oil the foil. Set the salmon, skin side down, in the pan. Roast the salmon, uncovered, until it changes color in its thickest part, about 15 minutes; check with the point of a thin knife. Using a fish spatula or one or two slotted spatulas, transfer the salmon carefully to a plate, leaving its skin attached to the foil if possible. Set aside to cool.
Step 4To make the dressing, whisk together the remaining 1 tablespoon plus 1 1/2 teaspoons wine, the remaining 6 tablespoons olive oil and a pinch of salt in a small bowl. Add the minced shallot, a pinch of freshly ground black pepper and a pinch of cayenne pepper, along with 1 tablespoon dill. Taste a little dressing on a spinach leaf and adjust the seasoning. Add a few drops of lemon juice, and the Dijon mustard, if desired. Taste again and adjust the seasoning.
Step 5Assemble the salad: In a large bowl, combine the spinach and the red onion. Add 4 or 5 tablespoons of the dressing, or enough to moisten the mixture, and toss. Set aside 1 teaspoon currants or cranberries. Add the remaining currants or cranberries to the salad and toss. Taste and adjust the seasoning if desired.
Step 6Spoon the spinach salad onto a platter or into a shallow serving bowl. Set the salmon on top. Spoon 1 or 2 tablespoons dressing evenly over the salmon. Sprinkle the salmon lightly with most of the chopped dill reserved for garnish. Sprinkle the spinach salad with the reserved currants or cranberries.
Step 7Put the diced hard-boiled egg in a small dish, sprinkle it lightly with salt and freshly ground pepper and mix gently.
Step 8Garnish the center of the salmon with a row of diced hard-boiled egg, top the egg with a row of chopped walnuts and sprinkle the garnish lightly with the remaining chopped dill. Serve at room temperature, with any remaining dressing in a small bowl.