Bring 6 cups of water to a boil in a saucepan. Add the soba noodles and cook, stirring occasionally with a wooden spoon, for 5 minutes or until al dente. Drain and refresh under cold water — this will prevent the soba noodles sticking together. Return the noodles to the pan, drizzle over 2 tbsp of the sesame oil and mix to combine.
Heat the olive oil and cashews in a small saucepan over medium heat and roast, stirring often to avoid burning the nuts, for 2 minutes or until golden brown. Transfer the nuts to a small bowl, add the shoyu and stir to coat.
Heat the remaining 1 tbsp of sesame oil in a frying pan over medium heat. Add the carrot and the garlic and sauté for 2 minutes, then add a pinch of salt and the mirin and sauté for another minute.
Combine the soba noodle sauce ingredients in a small bowl.
Divide the soba noodles among plates and top with a generous amount of the sauce. Top with the carrot, cucumber, orange, radish, nori, pickled ginger, spring onion and cashews and enjoy with chopsticks.