Put the potatoes in a large pot and add salted water to cover. Bring to a boil over medium heat and cook until tender when pierced with a knife, about 20 to 30 minutes. Drain the potatoes and let chill overnight in the refrigerator.
Put the chiles over a gas flame or underneath the broiler and cook until they are blackened on all sides. Enclose them in a plastic bag and let stand for 10 minutes to steam, which will make them easier to peel. Peel, stem, and seed the chiles. Set aside.
Toast cumin seed in a dry skillet stirring often until fragrant, then grind to a powder.
Combine cream, onion, spices, lime juice and cilantro and stir until well combined. Fold into potatoes and add salt and pepper to taste
Note: Fresh Corn can be added to this salad to take it over the top.