Heat the oil in a frying pan over medium heat. Cook the pork, breaking up any lumps with a wooden spoon, for 5 minutes or until browned. Move pork to 1 side of pan. Add the onion to empty side of pan. Cook, stirring, for 3-4 minutes or until onion softens slightly.
Stir the pork and onion together until combined. Add curry paste, ginger and garlic. Cook, stirring, for 1 minute or until aromatic. Add tomatoes and coconut milk. Cook, stirring, for 2-3 minutes or until heated through. Add the lentils and spinach. Cook, stirring, for 2-3 minutes or until heated through and the spinach is slightly wilted.
