Wash the lemons and dab dry. Finely grate the zest of 1 lemon and squeeze the juice. Peel ginger and garlic. Dice ginger finely, press garlic through a garlic press.
Mix ginger, garlic, sambal oelek, sesame oil, lemon juice and zest. Wash the fish, dab dry and cut into 3-4 cm cubes. Mix fish and marinade and cover and refrigerate for at least 30 minutes.
Cut the remaining lemons into large pieces. Wash lemon grass and leaves and dab dry. Cut lemon grass in half lengthwise. Prick lemon leaves, fish and lemon pieces with a skewer and then skewer them on the lemon grass.
Season fish with salt. Heat the oil in a large pan and fry the skewers in portions for 3-4 minutes, turning them over, remove them and keep them warm. Wash coriander, dab dry and chop except for a little bit for garnishing.
Sprinkle over the skewers and serve immediately.