Don't ruin your salad by drowning it in dressing, especially the fat, sodium, and preservative-laden versions found on most salad bars. For the healthiest option, pack your own.
In a small bowl, whisk together vinegar, soy sauce, mustard, garlic, ginger, and pepper flakes. Add oil in a slow, steady stream until emulsified.
Refrigerate for up to 1 week.