Ingredients

• 1 6- to 7-oz. jar tuna packed in olive oil, preferably yellowfin
• 1/4 cup mayonnaise
• 2 Tbs. hot sauce, such as Cholula
• 2 Tbs. finely chopped sweet gherkins
• 1 Tbs. finely chopped fresh dill
• Freshly ground black pepper
• 4 slices seedless German pumpernickel
• 1 small lemon, cut into quarters
• 3 Tbs. finely chopped red bell pepper
• 2 Tbs. finely chopped red onion
• 1/2 Persian cucumber, very thinly sliced
• Flaky sea salt, for serving