Start by toasting the walnut pieces lightly in a small pan over medium heat until they start releasing their rich, nutty aroma. Set aside.
Take one orange and grate it over a small bowl until you have about 1 teaspoon of zest. Set the bowl aside - you will use it later for the dressing.
Supreme both oranges: peel oranges with a knife, removing all white pith. Section oranges over another bowl. Squeeze out any remaining juice from the membranes and discard them.
Place raisins in a small microwavable bowl. Holding back the orange sections, tilt the orange bowl and pour all the collected orange juice over the raisins. You should have about ¼ cup of juice, or just enough to cover the raisins. If needed, add an extra tablespoon of water.
Microwave the raisins on high for 1 minute. Then, transfer them (and any leftover juice) to a large bowl and let them cool down a bit.
To the bowl with the orange zest, add olive oil, vinegar, shallot, mustard, salt, and pepper. Whisk everything together until it's well combined and emulsified.
Slice cabbage thin with a food processor with blade at level 2 or 3, or with a knife or mandolin if you prefer.
Add the sliced cabbage to the large bowl with the raisins. Drizzle the dressing over the top and toss gently to ensure everything is evenly coated.
Add in orange segments, reserving a few pieces for presentation. Toss again gently.
Divide the salad evenly among 6 plates. Sprinkle the toasted walnuts on top and add a few slices or crumbles of cheese. And don't forget those reserved orange segments for a picture-perfect presentation.