Place the jalapeno, scallions and lime juice in a bowl and set aside in the refrigerator.Season both sides of the salmon pieces with salt and pepper. Place a large skillet over medium-high heat and add in the olive oil. Once oil heats, add in the crushed ginger, stir and add in the salmon. Cook for 3 minutes, flip over, and cook another 5 minutes or until salmon flakes easily with a fork.While the salmon is cooking, place a medium saucepan over high heat, add in the vegetable stock and water, and bring to a boil. Once the soup is boiling, ladle out about 1/3 cup of the soup into a bowl. In that bowl, add the miso paste and whisk until it dissolves. Pour this miso broth back into the saucepan and lower the heat to a high simmer. Add the soy sauce, zucchini noodles and pepper to the soup. Let cook for 2-3 minutes or until zucchini noodles soften to al dente or your preference.Ladle the soup into two bowls, add the seared salmon and top with jalapeno-green onion relish.