Black Rice Salad with Mango and Peanuts

Name: Black Rice Salad with Mango and Peanuts
Ingredients: 2 oranges; 1/4 cup (or more) fresh lime juice; 2 tablespoons vegetable oil; 1 tablespoon fish sauce (such as nam pla or nuoc nam; optional); 2 cups black rice (preferably Lotus Foods Forbidden Rice); Kosher salt; 2 just-ripe mangoes, peeled, pitted, cut into 1/2 dice; 1 cup fresh cilantro leaves; 1 cup finely chopped red onion (about 1/2 large onion); 1/2 cup unsalted, dry-roasted peanuts; 6 scallions, thinly sliced; 2 jalapeños, seeded, minced