Preheat the oven to 450 degrees . In a small saucepan, bring the cranberries, 2 tbsp. EVOO, the lime juice, sugar and 1/4 cup water to a boil. Add the zest, cover and remove from heat.
In a large bowl, combine the sweet potatoes, coriander, cumin and remaining 4 tbsp. EVOO. Season; toss to coat the potatoes. Spread on a large foil-lined baking sheet and roast for 15 minutes.
Pour the cranberry mixture over the potatoes; toss to coat. Continue roasting until the potatoes are tender, about 15 minutes. Season; toss with the cilantro.