Soak 12 wooden skewers, 15 cm long, in water for approx. 1 hour. This way they won`t burn while frying.
Cut the pork into 2 cm cubes. Put the oregano, lemon juice, garlic and half of the pepper in a bowl. Add the pork steaks and stir until the mixture covers them well. Cover and chill for 1 hour.
Mix the additional lemon juice with the oil, salt and remaining pepper in a small mixing bowl. Put the meat on the wooden skewers. Preheat the oven grill to the highest setting and grill the souvlaki for 8-10 minutes, turning once. Arrange on a platter and drizzle with the lemon mixture. Serve hot and serve with tzatziki as a side dish.
Note: if the meat is marinated a few hours longer, it will taste even better.