Salmon Burgers with Ginger Mustard Mayonnaise

Mayonnaise: In a small bowl whisk together mayonnaise ingredients. Salmon Burgers: Discard any bones in salmon and finely chop salmon by hand. In a bowl stir together salmon, mustard, ginger root, soy sauce, and salt and pepper to taste and form into two 3-inch patties. In a non-stick skillet heat oil over moderate heat until hot but not smoking and saute patties 4 minutes on each side, or until just cooked through. Transfer salmon burgers to buns and top with mayonnaise, onion, and tomato.