Toss the sliced Fuji apples with 1 tablespoon of fresh lemon juice in a medium bowl to prevent browning.
In a large salad bowl, combine the mixed greens as a base for your salad.
Add the toasted walnuts to the greens.
Sprinkle the dried cranberries evenly throughout the salad.
Gently fold in the crumbled goat cheese.
Add the lemon-coated apple slices and optional red onion, distributing them evenly.
For the vinaigrette, whisk together the remaining tablespoon of lemon juice, olive oil, honey (if using), Dijon mustard (if using), and a pinch of salt and pepper until emulsified.
Drizzle the dressing over the salad just before serving, then gently toss to coat all ingredients.
Serve immediately for best flavor and texture.