In a small bowl, combine 1 tbsp olive oil, oregano, salt, and black pepper. Brush the mixture evenly over both sides of the tuna steaks.
Heat the remaining 1 tbsp olive oil in a nonstick skillet over medium-high heat. Add the tuna steaks and sear for approximately 2-3 minutes per side, depending on thickness and desired doneness.
Reduce the heat to low. Add the minced garlic to the skillet and cook for 20–30 seconds until fragrant, gently stirring it into the oil and spooning it over the tuna.
Remove the skillet from the heat. Drizzle the tuna steaks with lemon juice and sprinkle with chopped fresh parsley.