Mix almonds, parsley, lemon peel, about 1/8 teaspoon salt, and 1/8 teaspoon pepper on plate. Place flour on another plate. Sprinkle salmon with salt and pepper. Dredge salmon in flour, shaking off excess. Lightly brush 1 side of salmon with beaten egg. Press brushed side of salmon into almond mixture, pressing lightly so that almond and seasoning mixture stick.
Heat 1-2 tablespoons oil in a heavy large skillet over medium heat. Add salmon to skillet, almond-coated side down, and cook until crust is brown, about 5 minutes. Turn salmon over. Sauté until salmon is cooked through and opaque in center, about 5 minutes. Transfer salmon to plates. Serve with lemon slices.