Citrus Salad with Arugula & Ricotta Salata

Ingredients

• 5 tbsp. white balsamic vinegar
• 1⁄2 small red onion, halved and thinly sliced crosswise
• 2 blood oranges, peeled, pith removed, and sliced crosswise 1/4" thick
• 1 Cara Cara orange, peeled, pith removed, and sliced crosswise 1/4" thick
• 1 navel orange, peeled, pith removed, and sliced crosswise 1/4" thick
• 2 tbsp. roughly chopped mint leaves
• 2 tbsp. roughly chopped, roasted, salted pistachios
• 3 cups packed baby arugula
• 2 tbsp. olive oil
• Kosher salt
• freshly ground black pepper
• 2 tbsp. crumbled ricotta salata