For dressing, whisk mayonnaise, maple syrup, vinegar and sugar in a medium bowl til blended. Gradually whisk in oil until the mixture begins to thicken.
For salad, toss greens, apples, cherries and ¼ cup walnuts in a large bowl to combine. Toss with enough dressing to coat.
Divide salad into serving dishes and sprinkle with remaining walnuts.