Combine the chopped mango, cilantro, minced garlic and lime juice in a bowl; season with salt and pepper to taste, then refrigerate until ready to serve.
In a small bowl, mix the paprika, cayenne, chopped thyme, chopped oregano and kosher salt to make the blackening spice.
Spread the spice mixture on a plate and press each salmon piece into the spices to coat the flesh side evenly.
Heat a large heavy-bottomed pan or cast iron skillet over medium heat and generously spray with cooking oil.
When the skillet is hot, place the salmon fillets flesh-side down and cook 2 to 3 minutes until a dark crust forms.
Carefully flip the fillets with a spatula and cook an additional 5 to 6 minutes, until the salmon is cooked through and the skin is charred.
Serve each salmon fillet topped with a generous scoop of mango salsa.