Meanwhile, mix the soy sauce and sugar in a shallow dish. Place the salmon, flesh-side down, in the marinade and set aside.
Slice the peel off the oranges and cut each one into four discs.
Add a cup of cold water to the pan of boiling water, followed by the noodles (this will help them cook slower without going soggy). Cook until al dente, about 7 minutes, adding the beans for the last 5 minutes. Drain, rinse under cold water, then leave to one side.
Heat your grill to medium–high. Remove the salmon from its marinade and place skin-side down on a tinfoil-lined baking dish. Grill for 4 to 5 minutes, until crisp at the edges.
Toast the sesame seeds over a medium heat for 1 minute, or just until you can begin to smell them. Remove from the heat and set to one side.
Meanwhile, peel and finely chop the shallots for the dressing.
Finely grate the zest of the yuzu or grapefruit, then cut in half. Add three tablespoons of juice to a bowl with the chopped shallot and zest.
Peel and finely grate the ginger, then add about 1 tablespoon to the bowl of dressing.
Finely grate in the zest of the lime and orange, then squeeze in the juice of both. Mix the dressing together well, loosening with a splash of water, if necessary.
Arrange the beans and noodles on four plates. Top with the salmon, orange slices and the dressing. Slice the chilli and sprinkle it over the noodles along with the toasted sesame seeds.