How to Make It
Preheat grill to high (450°F to 550°F). Place peaches, cut sides down, on oiled grates; grill, uncovered, until well charred, about 4 minutes, turning to grill on all sides.
Toss together arugula, feta, mint, and pistachios in a large bowl.
Whisk together olive oil, vinegar, lemon juice, mustard, honey, salt, and pepper in a medium bowl until well combined. Drizzle vinaigrette over arugula; toss to combine. Serve grilled peaches over salad.