Place all ingredients for the marinade in a bowl and whisk together until combined.
Pound chicken flat then place chicken in a large plastic bag and pour the marinade on top. Place in fridge to marinate overnight.
Place all ingredients for the mango salsa in a bowl and toss until combined.
Heat up grill pan and grease. Remove chicken from marinade and discard marinade. Place on hot grill pan, sprinkle with salt, cook 5-7 minutes per side, until grill marks show up.
Once cooked through and no pink remains (165 degrees F), top with mango salsa and serve!