Preheat the oven to 400°F.
In a roasting pan, toss the potatoes with 1 tablespoon of olive oil and salt. Roast for 40 minutes, until tender.
Meanwhile, in a small bowl, whisk together the soy sauce, ginger, maple syrup, vinegar and mirin. Set aside.
In a large sauté pan, heat the remaining olive oil over medium-high heat and add the salmon. Pour half of the soy-ginger mixture into the pan and cook the salmon for 4 minutes per side. Transfer the cooked salmon to each of 2 serving plates. Add the remaining soy-ginger mixture to the pan and warm over medium heat.
Remove the potatoes from the oven and divided between the two plates. Pour the warmed soy-ginger sauce over the potatoes and the salmon and serve while hot.