Cook the rice in 2 cups of water.
Process fish in a food processor until a coarse paste forms. Transfer to a large bowl. Add garlic, 1 chopped chilli and chopped coriander, then season to taste with salt and pepper. Shape heaped tablespoonfuls of mixture into ‘cakes’.
Using a teaspoon, remove seeds from cucumbers. Discard seeds then slice cucumbers thinly on the diagonal. Place cucumbers, shallots, remaining chilli, lime juice, fish sauce and sugar in a bowl. Cover and refrigerate until ready to serve then gently stir in coriander leaves.
Meanwhile, heat oil in a non-stick frying pan over medium heat. Cook fish cakes, in batches, for 2 minutes each side or until golden and cooked through. Drain on paper towels.
Serve with pickled cucumber, rice and lime wedges.