Combine beans, Dijon, honey, salt, pepper, and vinegar in a blender or food processor. Pulse until very smooth.
Add water 1 tablespoon at a time, pulsing after each, until dressing is smooth and pourable. Store chilled in an airtight container up to 5 days.
Notes
Without any oil, this dressing is not 100 percent completely smooth in texture. Feel free to add a few teaspoons of olive oil for enhanced flavor and texture if you are okay with a little bit fat in your dressing!