Wild Salmon with English Peas and Mustard Beurre Blanc

Name: Wild Salmon with English Peas and Mustard Beurre Blanc
Ingredients: 1 cup shelled green peas (from 1 pound in pods), or 1 cup frozen peas, thawed; Coarse salt and freshly ground pepper; 1 side wild sockeye salmon (1 ¼ pounds); 1 tablespoon extra-virgin olive oil; 1 shallot, minced; ¾ cup dry white wine, such as Sauvignon Blanc; ¼ cup champagne vinegar; 1 tablespoon whole-grain mustard; 1 stick cold unsalted butter, cut into tablespoons; 2 tablespoons finely sliced chives, for serving; Flowering pea shoots, for serving (optional)