Heat 1 Tbsp olive oil over medium-high heat in a medium size skillet. Add the chicken pieces in an even layer and cook undisturbed for 4 minutes. Flip and cook for an additional 3 minutes until the chicken reaches an internal temperature of 165°F.
In a small bowl, whisk together mayonnaise, sugar and squeeze of lemon for the dressing, then set aside.
In a separate bowl, add chopped apples to a large bowl and squeeze lemon juice over them to prevent them from browning.
Add cooked chicken, grapes, blueberries, and dried cranberries.
Combine both sets of ingredients into one large bowl, cover with plastic wrap, and chill until ready to serve.
Serve over a bed of spinach.