Smoked Mackerel and Cucumber Salad

Adapted from Fresh by Michele Cranston
1 long english cucumber
1 smoked mackerel fillet
2 tablespoons chopped dill
3 tablespoons mayo
2 tablespoons milk
salt & pepper
1 bunch watercress
1 teaspoon dijon mustard.

Slice cucumbers. Combine chopped dill, mayo, s&p and dijon mustard, whisking till smooth. Toss cucumbers in dressing. Placce watercress on plate. Top with shredded mackerel fillets and dressed cucumbers. Drizzle excess dressing over a salad.