Chop the nuts. In a saucepan, gently heat the oil, honey, teff flakes, and walnuts, stirring until warmed through. Add the orange and grape juice, dried apricots, and dried bananas. Remove from the heat. Spread the dough in the pan, smoothing it out on the work surface with a wet spoon. Bake at 130°C (265°F) for about 13 minutes. Let it cool until lukewarm. Cut the bars while the dough is still warm using a serrated knife.