Remove any skin and bones from smoked trout fillets. Use your fingers or a fork to flake the trout into bite-sized pieces and place in a medium mixing bowl.

Mix dressing

In a small bowl combine Greek yogurt, mayonnaise, Dijon mustard, lemon juice and lemon zest. Whisk until smooth and homogenous.

Combine salad

Add the diced celery, finely diced red onion, chopped capers, chopped dill and chives to the bowl with the flaked trout. Pour the dressing over the trout mixture. Gently fold everything together with a rubber spatula or spoon until evenly coated, taking care not to mash the trout too much.

Season

Season the salad with sea salt, freshly ground black pepper and hot sauce (if using). Taste and adjust seasoning — add a bit more lemon juice for brightness or a pinch more salt if needed. Cover and chill for 15–20 minutes to let flavors meld (optional but recommended).

Sandwich Build & Serve

Prepare bread

Lightly butter one side of each rye bread slice if you prefer toasted sandwiches. Heat a skillet over medium heat and toast buttered bread, butter-side down, until golden and crisp, about 1–2 minutes per side. Alternatively, leave bread untoasted.

Assemble sandwiches

On 4 slices of rye bread (to make 4 sandwiches), place 1 leaf of lettuce each. Divide the smoked trout salad evenly among the 4 leaves (about 2 oz trout salad per sandwich). Top the salad with 2–3 tomato slices and a few thin red onion rings. Place the remaining bread slices on top to close the sandwiches.

Slice & serve

Using a sharp knife, cut each sandwich in half on the diagonal or down the middle. Serve immediately with lemon wedges on the side for squeezing over the filling.

Storage

Leftover smoked trout salad will keep in an airtight container in the refrigerator for up to 2 days. Assemble sandwiches just before serving to keep bread from becoming soggy.