Using a small food processor or a narrow, tall container ideal for an immersion blender, combine rhubarb juice, honey, red wine vinegar, mustard, salt and pepper. Blend well.
Slowly blend canola oil into rhubarb mixture to create a creamy dressing.
Stir in poppy seeds.
Drizzle over prepared salad.
Notes
To get a creamy texture that will stay blended, it's important to add the canola oil slowly with the blender going. This dressing can be stored in the fridge for 5 days.