Place 4 skinless, boneless chicken thighs on a cutting board and pat dry with paper towels. Sprinkle all over with 1 Tbsp. Diamond Crystal or 1¾ tsp. Morton kosher salt and 2 tsp. freshly ground black pepper, pressing gently to adhere. Using a Microplane, finely grate zest from 1 lemon and 2 limes over both sides of chicken, pressing again to adhere.