Turkish Fish Sandwich

Name: Turkish Fish Sandwich
Cuisine: Middle Eastern
Ingredients: 4 fresh fillets of mackerel (or substitute with another firm white fish like sea bass); 2 tbsp olive oil; Salt and black pepper to taste; 1 tsp paprika; 1/2 tsp cumin; 1 medium red onion, thinly sliced; 1 large tomato, sliced; 1/2 small head of lettuce, shredded; Fresh parsley, a handful of leaves; 4 Turkish bread rolls or sub style sandwich rolls; Lemon wedges for garnish