01 - Rinse quinoa thoroughly under cold running water. In a medium saucepan, combine quinoa with water. Bring to a boil, then reduce heat to low, cover tightly, and simmer for 15 minutes or until water is absorbed. Remove from heat and let rest, covered, for 5 minutes. Fluff grains gently with a fork and allow to cool to room temperature.
02 - Preheat a grill or grill pan over medium-high heat. Lightly brush peach halves with olive oil. Place on grill, cut side down, and cook 2–3 minutes until grill marks appear and peaches have softened. Remove from grill and slice when cool enough to handle.
03 - In a small bowl, whisk together extra-virgin olive oil, honey, lemon juice, Dijon mustard, salt, and black pepper until emulsified.
04 - In a large mixing bowl, combine cooled quinoa, grilled peach slices, cherry tomatoes, red onion, cucumber, basil, and arugula or mixed greens.
05 - Drizzle salad with prepared lemon-honey vinaigrette. Toss gently until evenly coated.
06 - Top salad with crumbled feta cheese and toasted nuts, if desired. Serve at once or refrigerate up to 2 hours before serving to enhance flavors.