In a medium bowl mix together sour cream, mayonnaise, lime juice and zest, salt, cayenne pepper and oregano. Mix well.
For Potato Salad
Put potatoes in a large pot of salted water; bring to a boil. Cook until just tender, 20 to 25 minutes. Add carrots for last 5 minutes of cooking. Cool potatoes and carrots. Cut potatoes into bite size pieces and grate carrots.
Prepare ingredients above.
Mash about 2 cups of potatoes. Mix dressing with mashed potatoes. Then add cilantro, onions, jalapeños to creamy mixture.
Add frozen peas and grated carrots to mixture. Pour dressing mixture over remaining potatoes and blend gently. Refrigerate 1-2 hours until cold.