Lightly brush the salmon fillets all over with olive oil. Season with salt.
Place the salmon on the pre-heated hotplate, skin side down, for 4 minutes. Turn the fillets and barbecue for another 2 or 3 minutes.
To make the salad:
Peel the cucumbers. Use a vegetable peeler to slice strips of cucumber from one end to the other. Discard the centre seeds.
Place cucumber in a colander and allow to drain for around 30 minutes.
Toss cucumber with the chopped coriander, shallots and chilli, and set aside until ready to serve.
To make the dressing, in a bowl dissolve the brown sugar in the lime juice and fish sauce, then whisk in the vinegar. Season with black pepper and add the peanut oil. Mix well before pouring over salad to serve with salmon.