Heat a barbeque plate on medium and the barbeque grill on medium-high. Brush the salmon with the oil and rub with the spices. Slice the potatoes.
Melt butter on the barbeque plate. Add the potato slices and cook, turning once, for 7-8 minutes, until golden. Add salmon to the grill and cook for 3-4 minutes each side. Transfer the salmon to a plate and the potato to a bowl.
Place watercress salad and cucumber in a bowl. Break the salmon into large chunks. Add to the salad with the potato slices. Toss gently to combine.
Combine the mayonnaise with 1-2 tablespoons hot water, to make a pouring consistency. Drizzle over the salad and serve.
Serving size: 4
Recipe courtesy of taste.com.au