How to Make It
In a blender, combine the mustard, shallot, garlic, clam juice and vinegars and mix until smooth. With the machine on, add the oil in a thin stream and process until emulsified. Season with salt and pepper.
Puree the chives with the canola oil in a blender until smooth. Season with salt.
Bring 2 medium saucepans of salted water to a boil. In one, cook the potatoes until just tender, about 10 minutes. Drain and cool in a bowl of ice water; drain again and pat dry. In the other, cook the asparagus until crisp-tender, about 3 minutes. Drain and cool under running water, then pat dry. Cut the asparagus into 1/2-inch lengths.
In a large, deep skillet, fry the bacon in 1 teaspoon of the olive oil over high heat until crisp, about 5 minutes. Drain the bacon on paper towels and coarsely chop it. Pour off the fat and wipe out the skillet.
Heat the remaining 2 teaspoons olive oil in the skillet. Add the potatoes and bacon and cook over moderately high heat, stirring, until the potatoes are just beginning to brown in spots, about 6 minutes. Add 1/2 cup each of the chicken stock and clam juice and cook, stirring gently, until most of the liquid is absorbed, about 6 minutes. Stir in the asparagus, butter, chives, dill and the remaining 1/4 cup each of chicken stock and clam juice. Cook until most of the liquid is absorbed, about 5 minutes. Season with salt and pepper and keep warm.
Heat a cast-iron grill pan or skillet. Season the salmon with salt and pepper and grill over high heat until browned on the bottom, about 3 minutes. Turn the salmon and cook until golden and crusty, about 2 minutes longer. Spoon the potato hash onto 4 plates and top with the salmon. Drizzle the garlicky vinaigrette and chive oil all around and serve immediately.