Peel and section oranges and grapefruit over a large bowl, reserving juice; add sections to juice. Add jicama and radishes to orange mixture; toss gently. Cover and chill 30 minutes.
Combine rind and next 6 ingredients (through salt) in a small bowl, stirring until smooth. Arrange lettuce in a large bowl. Using a slotted spoon, place the orange mixture over lettuce; drizzle evenly with yogurt mixture. Sprinkle with pomegranate seeds, pumpkinseed kernels, and cilantro.
Wine note: Sparkling wine deserves a place at every holiday table, both for its celebratory allure and compatibility with many foods. When celebrating Santa Fe style, look for Gruet Brut NV ($14) from New Mexico. Made in the manner of true Champagne, it has lemony acidity that stands up to the acid of the yogurt dressing, while crisp grapefruit flavors echo the salad's citrus elements. --Jeffery Lindenmuth