Coarsely chop the smoked salmon and set aside.
Place the grated zucchini in a clean kitchen towel and squeeze out as much moisture as possible.
In a large bowl, combine the zucchini, grated potato, spring onions, egg, and flour. Season with salt and pepper and mix gently until evenly combined.
Heat enough vegetable oil in a large frying pan to cover the base by about 5 mm over medium heat.
Working in batches, spoon heaped tablespoons of the mixture into the pan and gently flatten into 4 cm rounds.
Cook for about 3 minutes per side or until the fritters are golden brown and crisp.
Transfer cooked fritters to a paper towel-lined plate to drain excess oil.
Arrange the Zucchini Fritters with Smoked Salmon on a serving platter.
Top each fritter with a dollop of sour cream, pieces of smoked salmon, lemon zest, and fresh dill.
Serve immediately while warm