Step 1Slice the morels in half lengthwise and brush or shake off any debris; wash them only if absolutely necessary, and drain thoroughly. Slice the brown mushrooms 1/4-inch thick. Remove the peas from the pods, or if using sugar snaps, trim and string the pods. Blanch the peas in lightly salted water until they're crisp-tender and rinse them with cold water to stop the cooking.
Step 2Melt the butter in a medium skillet over medium-high heat and add the mushrooms. Cook the mushrooms until they begin to color, 2 to 3 minutes, then add the green onion, 1 thyme sprig and a dash of salt and pepper. When the mushrooms begin to release their liquid, add the wine and soy sauce and cook until nearly dry, 1 minute. Add the cream and peas, bring to a boil, then reduce to a simmer.
Step 3Meanwhile, season the salmon lightly with salt and pepper and heat the oil in another skillet (preferably nonstick). Cook the salmon over high heat until nicely browned and a skewer slides in easily, 3 to 4 minutes per side. Transfer the salmon to a serving dish or individual plates. Correct the seasoning of the mushroom-pea mixture and spoon it around the salmon. Garnish with more fresh thyme if desired.