Grilled Chicken and Spinach Salad with Honey Mustard

Chicken breast, boneless skinless

medium clove Garlic

Mango, pitted

Red onions, halved and sliced thin (about 1 cup), small

Dijon mustard

Honey

Kosher salt and freshly ground black pepper

Olive oil

White vinegar

Pepitas, toasted

6 ounces baby spincach