Trim excess fat from chicken. If necessary, pound chicken to an even 1/2-inch thickness using a mallet, rolling pin or cast iron skillet (this will ensure the chicken cooks evenly). Place oil, lemon juice and spices in a large resealable plastic bag. Add chicken. Seal bag and turn to thoroughly coat chicken. Refrigerate until ready to grill chicken.
Grill chicken over direct high heat for 6 to 8 minutes. Turn chicken and continue to cook for 6 to 8 minutes until cooked through. Transfer cooked chicken to a serving plate.
Combine salsa ingredients in a bowl; stir and season to taste with salt and pepper. (Can be made up to 8 hours ahead and refrigerated until ready to serve.)
Top grilled chicken with mango salsa and serve immediately.
Recipe Tip: Try slicing the chicken onto warm, low-fat tortillas, top with mango salsa and crumbled queso fresco cheese for delicious spicy chicken wraps.