Smoked paprika mackerel with gazpacho salad

Name: Smoked paprika mackerel with gazpacho salad
Ingredients: 120 gm crustless day-old sourdough bread, coarsely torn; 90 ml sherry vinegar; 100 ml olive oil; 200 gm each of cherry tomatoes and yellow grape tomatoes, halved; 1 oxheart tomato, coarsely chopped; ½ Spanish onion, thinly sliced; ½ garlic clove, finely chopped; 1 char-grilled red capsicum, coarsely torn (see note); 1 Lebanese cucumber, half-peeled, coarsely chopped; 8 slimy mackerel fillets, pin-boned; 1 tsp smoked sweet paprika