In a small bowl, whisk together the miso, soy sauce or tamari, mirin or vinegar, ginger, and honey. On a baking sheet lined with parchment paper, arrange the salmon and brush with the miso mixture. Let the salmon stand for 10 minutes.
Bake the salmon for 10 minutes, or until opaque.
Meanwhile, separate the bok chou stems from the leaves. Slice the stems into thin strips and slice the leaves in half.
In a wok or large skillet over medium heat, heat the oil. Cook the sliced bok choy stems, shallots and garlic for 3 minutes, or until the stems are tender. Stir in the bok choy leaves and lemon peel and cook just until the leaves wilt slightly. Remove from the heat, stir in the lemon juice, and season with salt to taste.
Place the salmon and bok choy on 4 plates and sprinkle with the sesame seeds and scallion.