Place Fresh Oregano (2 tablespoon), Ground Black Pepper (to taste), Kosher Salt (to taste), Crushed Red Pepper Flakes (2 teaspoon), Garlic (4 clove), Fresh Parsley (1/4 cup), and Red Wine Vinegar (3 tablespoon) in a bowl and stir together.
Add Extra-Virgin Olive Oil (1/2 cup) and let stand 15-20 minutes before serving.
Place the Pork Tenderloin (2) on a baking sheet or in a casserole dish. Season them with Kosher Salt (to taste) and let them come to room temperature, for up to two hours. Meanwhile, heat a grill to medium-high.
Place pork tenderloins over direct, medium-high heat and grill for about 6 minutes per side. Pork tenderloin has three sides, so this will total about 18 minutes. Cook to an internal temperature of 140 to 145 degrees F (60-65 degrees C).
Let it rest 5-10 minutes before slicing. Top with chimichurri sauce and serve.