In a small bowl, add the paprika, cayenne, thyme and oregano and salt and mix to blend. Put the mixture on a plate or other flat surface and coat the portions of salmon, 1 at a time, on the flesh side only.
Heat a large heavy-bottomed pan or cast iron skillet over medium heat, and add the oil. When the oil begins to smoke quite heavily shut the heat off under the pan. Add the salmon, 1 at a time, in a single layer, flesh side down, in the oil. Turn the heat back on under the pan and cook for 2 to 3 minutes. Use a spatula to turn the salmon to the other side. Cook the salmon over medium heat, until the skin becomes crispy, about 5 to 6 minutes.
Arrange the salmon on a platter, sprinkle with lemon zest and lemon juice and serve immediately.