Wash and dry the greens and blueberries thoroughly. Thinly slice the cucumber and red onion (if using). Roughly chop the roasted pistachios.
In a small jar or bowl, combine lemon juice, lemon zest (if using), honey, and Dijon mustard. Whisk vigorously while slowly adding the olive oil until emulsified. Season with salt and pepper.
In a large bowl, add mixed greens, blueberries, cucumber, and red onion. Drizzle about two-thirds of the dressing over the salad and toss gently to coat.
Top the salad with chopped pistachios and crumbled feta. Add remaining dressing to taste. Garnish with edible flowers or microgreens if desired and serve immediately.
Notes
Toast pistachios briefly in a dry skillet for 2–3 minutes to enhance flavor.
Store dressing separately and add nuts just before serving to preserve crunch.
Swap lemon for orange in the dressing for a sweeter variation.
Turn into a main by adding grilled chicken, shrimp, or cooked grains like quinoa.