Begin by combining the red wine vinegar, grenadine and sugar. Mix well and add the diced red onion for 20 - 30 minutes. Once complete, combine with the mango and set aside.
Heat a cast iron skillet with the oil on medium heat. Add the salmon flesh side down and cook for 2 minutes. Flip the salmon and add to a 325 oven for 10 minutes.
Finish composing the dish with the celery root puree and the tomatillo salsa on the side of the Salmon topped with the mango salsa.