In a small bowl, whisk together the orange zest, lemon zest, orange juice, lemon juice, olive oil, honey, salt, pepper, and crushed red chili flakes until emulsified. The citrus zests add bright, complex flavor while the honey balances the acidity. Set the dressing aside at room temperature so the flavors can meld while you prepare the other components.

While the dressing sits, prepare your salad base: tear or roughly chop the arugula into bite-sized pieces, tear the mint leaves by hand (this prevents bruising and keeps them tender), thinly slice the red onion into half-moons, and slice the cucumber into half-moons or thin rounds. Place all the prepared vegetables in a large salad bowl. I like to keep these components separate from the dressing until the last moment so the arugula stays crisp and doesn't wilt prematurely.

Heat a grill pan or skillet over medium-high heat until it's very hot. Working quickly, grill the peach wedges 2 minutes per side until they develop golden-brown char marks and caramelize slightly—this brings out their natural sweetness. Transfer to a plate. Without washing the pan, immediately grill the halloumi slices 2 minutes per side until golden and slightly softened but still holding its shape. The residual peach juices add subtle flavor to the cheese. Both components should be warm when served, so time this step just before final assembly.

Add the warm grilled peaches and halloumi to the bowl with the prepared vegetables. Pour the citrus vinaigrette over everything and gently toss to combine, being careful not to break up the halloumi or crush the peaches. I find tossing with your hands gives you better control than utensils. Divide the salad among serving plates, then top each portion with a generous handful of crushed pistachios for a satisfying textural contrast and nutty finish.