1. Place a large steamer basket in a large, heavy-bottomed pot and add water to just below the steamer bottom. Add peas to the steamer and top with scallops in a single layer. Sprinkle with thyme, 1/4 teaspoon salt, and 1/4 teaspoon pepper.
2. Cover the pot and place over high heat. When steam begins to escape, start timing. Steam for 3 minutes. Add pea sprouts, cover, and continue steaming until the scallops are just cooked through (2-3 minutes). Remove from the heat.
3. Whisk oil, lemon zest, lemon juice, and the remaining 1/4 teaspoon salt and pepper in a small bowl until combined. Spoon the scallops, peas, and pea sprouts onto a serving platter. Drizzle with the dressing and serve immediately.