First, salt the zucchini and place in a colander. Leave it there for about 20 minutes to release moisture. Then, squeeze it very well to get it as dry as possible (you could reserve the salty zucchini juice for another use if you can think of any, let us know if you do).
In a food processor, blend half of the fish, onion, parsley, dill, lemongrass, lemon zest, and the spices, until it sticks together and separates from the sides. This means the protein will hold the fish cakes together as we are not using any eggs and flour/bread in these.
Cut the rest of the fish into small dices, this will add texture.
Mix the zucchini, blended fish and cut fish all together. With wet hands, form a small patty and fry it to test for seasoning. Once seasoned, you can continue rolling the rest into small patties. Sear the patties in neutral oil, about 2-3 minutes per side, till well browned and firm to the touch.
Make the sauce by heating some olive oil and adding the garlic. After about a minute add the tomatoes, salt, and herbs, let it simmer for about 15 minutes and check for seasoning, if itβs still sour let it cook a little longer. Discard the herbs and garlic and blend the sauce until smooth.
To plate, add some of the sauce, a few fish cakes. spoon a dollop of yogurt, and sprinkle with chopped herbs, chili, and a drizzle of olive oil.