In a medium bowl, whisk together the orange juice, lemon juice, apple cider vinegar, Dijon mustard, honey, salt, and pepper. Slowly stream in the olive oil while whisking continuously until the dressing is smooth and emulsified.
Toast the walnuts or pecans in a dry skillet over medium heat until fragrant, then let cool and roughly chop.
In a large salad bowl, combine the mixed greens, diced apple, dried cranberries, toasted nuts, and crumbled blue cheese.
Drizzle the dressing over the salad and toss gently to combine. Serve immediately.