Roasted Yam and Potato Salad with Chipotle

Name: Roasted Yam and Potato Salad with Chipotle
Ingredients: * 1.5 pound yukon gold potato, or red potato, but not russet; * 1 large yam, about 1 lb; * 1 tablespoon olive oil; * 1 teaspoon ground cumin, or less; * 1 teaspoon chili powder; * 2 clove garlic, minced; * 1 teaspoon salt; * 1/2 teaspoon black pepper; * 2 slice bacon, chopped; * 4 green onion, optional; * 1 large poblano chile pepper, or green bell pepper, finely chopped; * 1/2 cup minced fresh cilantro, or less; * 2 hard cooked egg, chopped; * 1/3 cup mayonnaise; * 2 teaspoon chopped chipotle pepper in adobo sauce, minced (or less,; depending on your taste); * 1 teaspoon sugar; * 1 tablespoon lime juice; * 1/2 large ripe avocado, peeled and finely chopped (optional)