Shaved brussels sprouts heat up and sparkle with dried chile and Meyer-lemon juice. Quinoa and walnuts make the salad hearty.
Place quinoa and 1 1/2 cups water in a small saucepan with a pinch of salt. Bring to a boil, reduce heat to a simmer, and cook, covered, until grains are tender and water has been absorbed, about 16 minutes. Transfer to a bowl; let cool.
Peel 4 long strips of zest from lemon with a vegetable peeler; thinly slice. Juice lemon into a bowl (you should have 2 tablespoons); whisk in oil in a slow, steady stream.
Add zest, brussels sprouts, walnuts, scallions, and chile to quinoa. Season with 3/4 teaspoon salt and drizzle with vinaigrette. Stir to combine. Serve immediately, or refrigerate, covered, up to 3 days.