Place the baby greens in a large mixing bowl.
Gently fold in the blueberries, chopped pistachios, crumbled feta, and red onion.
In a separate small bowl, combine the olive oil, red wine vinegar, maple syrup, salt, and pepper. Whisk until smooth and well blended.
Pour the dressing over the salad mixture and carefully toss everything together, ensuring each leaf is lightly coated.
For optimal flavor, serve the salad right away, or let it sit in the refrigerator for about 20 minutes to enhance the taste.