Heat a cast iron pan or grill pan over medium high heat. Cut the oranges in half lengthwise, then in half again to make quarters. Once pan is hot, place the orange quarters, and the half of the lime in the pan, cut sides down. Cook until the flesh begins to char, about 2-3 minutes, then remove the lime and flip oranges to char the other cut side. Once all citrus is charred, remove from heat and let rest for about 5 minutes to cool.
Peel the rind off of the charred orange slices, then place them into a food processor. Squeeze the juice from the charred lime half into the food processor. Add the cilantro, mint, onion, garlic, chiles, and salt. Pulse until a finely chopped consistency is achieved about 20-30 seconds. Serve immediately, or store in the refrigerator.