Preheat the oven to 160 degrees, put sea salt on the baking tray, put the whole beets on top and bake for 30 minutes.
Slice the fennel and daikon into 1mm thick strips. Add olive oil and lemon juice.
Pour cold olive oil into a blender glass, add honey, mustard, beat for 30 seconds until the consistency of mayonnaise, add lemon juice at the end.
Cut the beets with a slicer into round slices 1.5 mm thick.
Arrange beetroot slices in circles on a round plate. Put the daikon, fennel and spinach leaves in the center of the beets. Sprinkle with chopped walnuts. Drizzle with honey mustard sauce.