Step 1
Place the potato in a large saucepan and cover with cold water. Bring to the boil over high heat. Cook for 15 mins or until tender. Drain well and return to the pan. Use a potato masher or fork to mash until almost smooth. Set aside for 5 mins to cool.
Step 2
Lightly whisk 1 egg in a small bowl. Add tuna, whisked egg, half the spring onion and half the dill to the potato and stir to combine. Season. Divide the tuna mixture into 12 even portions. Shape each portion into a 7cm patty.
Step 3
Lightly whisk the remaining eggs in a shallow bowl. Place the flour and breadcrumbs in separate shallow bowls. Coat 1 patty in the flour and shake off excess. Dip in the egg, then coat evenly in the breadcrumbs. Place on a large plate. Repeat with the remaining patties.
Step 4
Heat the oil in a large frying pan over medium heat. Cook the patties, in 2 batches, for 2 mins each side or until golden brown. Transfer to a plate lined with paper towel.
Step 5
Meanwhile, combine the mayonnaise, caper, and remaining spring onion and dill in a small bowl. Stir in enough hot water to loosen the sauce slightly.
Step 6
Serve patties and sauce with rocket, snow peas, peas and lemon wedges.