Using a sharp knife, peel the oranges, carefully removing all of the bitter white pith. Halve the oranges lengthwise and thinly slice them crosswise. In a medium bowl, toss the grilled onion with the oranges, cilantro, chipotles and 1 tablespoon of the lime juice; season with salt and pepper. In a small microwave-safe bowl, mix the orange marmalade with the adobo sauce and the remaining 1 tablespoon of lime juice. Microwave the marmalade until melted, about 10 seconds.