Heat half the oil in a large non-stick frying pan and fry the tuna steaks for 2 minutes per side. Remove 2 of them and cook the last one for 1 minute more on each side. Set the tuna aside, cover and keep warm. Clean the pan.
Heat the remaining oil, then add the vegetables and stir-fry for 2 minutes. Add the noodles and stir-fry for a further 2 minutes, mixing them in. Reduce the heat and add the ginger, garlic, orange zest and juice, jam and 50ml water. Stir-fry for 2 more minutes, until well combined and piping hot.
Divide the noodles between bowls and break up the tuna steaks on top. Sprinkle with coriander to serve.