Prepare the Salad: In a large bowl, combine mixed greens, strawberries, cucumber, red onion, feta cheese, and nuts. If using, add cooked quinoa and avocado slices.
Make the Dressing: In a small bowl or jar, whisk together olive oil, lemon juice, lemon zest, honey, Dijon mustard, and minced garlic. Season with salt and pepper to taste.
Dress the Salad: Drizzle the lemon vinaigrette over the salad and toss gently to combine.
Serve & Enjoy: Serve immediately as a refreshing side dish or top with grilled chicken or salmon for a complete meal.