Prepare the Brussels sprouts in the microwave according to package instructions, without any added seasoning.
While the Brussels are cooking in the microwave, whisk together the lemon garlic vinaigrette in a medium bowl: lemon juice, olive oil, garlic, salt and chili flakes (if using).
Add the cooked Brussels sprouts to the bowl and toss well. Sprinkle with scallions if you wish to serve.
Notes
Leftovers are a great way to add fiber and bulk to pastas and stir fries!