How to Make It
In a small saucepan, combine the wine, onion and saffron and bring to a simmer; let cool. Transfer the mixture to a blender, add the lemon juice and mustard and blend until smooth. Gradually blend in the oil in a thin stream. Transfer the vinaigrette to a bowl and season with salt and black pepper.
Spread the salmon out on a baking sheet. In a bowl, combine the coriander, cayenne and a pinch of salt. Lightly brush the salmon with vinaigrette and sprinkle liberally with the spice mixture.
Heat 2 nonstick skillets. When the pans are hot, add 2 salmon slices to each, spiced side down, and cook over high heat until opaque around the edges but slightly rare in the center, about 2 minutes. Flip onto 4 dinner plates, cooked side up; repeat with the remaining fish.
Scatter the bell peppers, nasturtium leaves and chives over the salmon. Drizzle with some of the vinaigrette and garnish with the flowers. Serve warm or at room temperature.