In a strong plastic bag, combine the salt, pepper, flour and shrimp. Shake well. Heat 2 tablespoons of the olive oil in a large skillet over high heat until very hot but not smoking. Add half of the shrimp; don't crowd. Cook the shrimp until golden brown and crisp, about 5 to 7 minutes; remove and place on a warm plate. Add the remaining olive oil and continue with the second batch of shrimp. Return the first batch to the pan and add the jalapenos and garlic. Cook for an additional 30 seconds. Add the butter and lemon and turn off the heat. Stir the butter into the shrimp until just melted and creamy. Adjust the seasoning with additional salt and pepper if desired.