Step 1Place sunflower seeds on rimmed baking sheet and toast at 350 degrees until lightly browned, about 15 minutes. Set aside to cool.
Step 2Slice pepper in half lengthwise, seed and cut crosswise into thin slices. Peel jicama and cut into 1x1/4-inch matchsticks. Slice grilled chicken into 1x1/4-inch matchsticks. Peel orange and remove white pith. Cut into thin wedges.
Step 3Toss together lettuce, Anaheim pepper, jicama, chicken, orange wedges and cilantro in large bowl.
Step 4Combine sour cream, mayonnaise, orange juice, salt, sugar and pepper to taste in small bowl. Add toasted seeds to salad bowl. Toss salad with dressing. Divide among 5 plates and serve immediately.