Trim and mince the green garlic stalks, include as much of the green stalk as you can (that said, be sure to trim off and discard any wilted or yellowing parts).
Mix the minced green garlic, oil, vinegar, salt, mustard, and pepper in a small mixing bowl or glass jar. Whisk together or cover jar and shake vigorously to combine.
Use the dressing within an hour or two if you want to see that vibrant green color.
Any longer and it will taste just as good, but the green will soften to a muted yellow. Keep the dressing covered and chilled up to three days; be sure to bring it up to room temperature before using it (the olive oil should be fully fluid).