Place the pork,peanuts,onions,ginger,zest,1 tbsp soy sauce,2 tsp maple syrup,chilli flakes and coriander into a large bowl,season well with salt and pepper,then mix well using your hands.Shape into 4 patties,cover and chill for at least 30 minutes.
Preheat the oven to 200 degrees and line a tray with baking powder.
Heat a frypan/chargrill pan over med-high heat.Brush the pan with a little oil and cook the patties for 1-2 mins each side until golden browm.Transfer the patties to the baking tray and bake for a further 8-10 mins,until cooked through.
Mix the oil with the remaining soy and maple syrup or honey in a small bowl and brush over the patties.
To serve sandwich each ciabatta with some chilli sauce,sour cream etc and a pattie.