In a medium bowl, whisk together the mayonnaise, lemon juice, salt, pepper, garlic powder, and onion powder until smooth. Set aside.
To a large mixing bowl, add the turkey, apple, celery, cranberries, green grapes, red grapes, pecans, and green onions. Add the dressing to the bowl and stir well-coated and combined.
Cover with plastic wrap, and chill for at least 2 hours before serving. I like to serve this salad over some lettuce leaves, but you can add it to your favorite bread or eat it with crackers.
Notes
You can serve the salad right away if you wish, it is just better if it has a chance to sit in the fridge and the flavors can mingle.
You can substitute shredded or diced cooked chicken instead of turkey.
Golden or regular raisins can be used in place of the cranberries.
Store any leftovers in the fridge in an airtight container for up to 3 days.