First, assemble the salad in a large bowl. Start by laying the cleaned dandelion greens. You can cut the leaves into 2-inch length for a better presentation.
Quarter the eggs and potatoes and lay it on the greens. Add the kidney beans.
To make the salad dressing, cook the bacon in a large heavy skillet till golden and crisp. Transfer to a cutting board and chop it finely. Reserve the bacon fat.
In a small bowl, whisk together cider vinegar, shallot, Dijon mustard, bacon fat, salt, and pepper. Since the bacon fat is salty, you may want to go easy on the salt.
Drizzle the dressing on the assembled salad and toss to coat the greens well. Sprinkle the chopped bacon on top.
For a vegetarian version, omit the bacon and eggs. Grate Parmigiano Reggiano on the salad to create the salty taste of the bacon.
Notes
You can substitute any yellow mustard for Dijon mustard.