In a small-mouth pint Mason jar, add the red wine vinegar, garlic, anchovies, anchovy oil if using and the preserved lemon. Place a blender's blade in the mouth of the Mason jar, and screw the base on firmly but not too tightly. Invert the jar, place the base on the blender and blend until completely smooth. (Alternatively, combine the ingredients in a food processor or mini-prep, or use an immersion blender.)
Invert the jar, remove the base and blade and add the olive oil and a pinch of salt and pepper. Reapply the base, and blend until emulsified, just a few seconds. Season to taste, and dilute by whisking in a small amount of water if a looser texture is desired.
This dressing will keep in the refrigerator, covered, about a week.