For the salad, cook the cauliflower and broccoli in boiling salted water for 4-5 minutes, then drain.
Heat the oil in a frying pan and lightly fry the onion for 3-4 minutes, then add the cauliflower and broccoli, chilli flakes and season with salt and freshly ground black pepper. Continue to cook for 5-6 minutes, stirring frequently, until the broccoli and cauliflower turn crisp, about 5 minutes. Remove from the pan and set aside.
Slice the sausage in half lenghtways and fry in the residual oil in the pan for 5-6 minutes, or until cooked through.
For the chilli tomato chutney, heat the olive oil in a frying pan and fry the onion for 4-5 minutes, or until starting to soften. Stir in the rest of the ingredients and bring to a simmer for 5-6 minutes, until the liquid starts to reduce.
Pile the broccoli and cauliflower onto a serving plate, top with the halved sausage, and spoon the chilli tomato chutney around the plate. Garnish with the chopped fresh chives and serve.