In a large mixing bowl, combine baby spinach and arugula.

Add the drained mandarin oranges, toasted walnuts, dried cranberries, and shaved Parmesan to the greens.

In a separate small bowl, whisk together the flaky sea salt, red wine vinegar, orange juice, honey, poppy seeds, Dijon mustard, and extra-virgin olive oil until well blended.

Drizzle the dressing over the salad and toss gently to combine.

Season with kosher salt and freshly ground black pepper to taste.