Combine bread, garlic, mint, lemon zest, salt, pepper, and cayenne in the bowl of a food processor; pulse until finely chopped.
Heat olive oil in a skillet over medium-high heat. Place salmon fillets, skin-side up, in the hot skillet and cook until edges are opaque, 3 to 5 minutes. Flip fillets and transfer to a baking dish, skin-side down. Press bread mixture over fillets.
Bake in the preheated oven until salmon can be easily flaked with a fork and the crust is browned, 15 to 20 minutes more.
