Heat olive oil and white balsamic vinegar in a pan with tomato stalks, sugar, and salt.
Add cherry tomatoes, remove stalks, add remaining sugar and pepper, then simmer for 8 to 12 minutes.
Transfer the tomato confit to a sterilised jar and allow to cool.
Fry onion, chilli, and garlic in olive oil until softened.
Stir in tomato purée, skinned tomatoes, salt, pepper, sherry vinegar, and sugar and cook until pulpy.
Blend the sauce until smooth and pass through a sieve into a clean bowl.
Fry shallot, chilli, and ginger in olive oil until soft then set aside.
Sieve the baked potato flesh into a bowl and mix with brown and white crabmeat.
Add the fried shallot mixture to the potato and crab.
Mix in lemon zest, chives, salt, pepper, and butter.
Form the mixture into balls with wet hands and chill in the fridge to set.
Heat oil in a saucepan or deep-fat fryer to 180°C.
Coat each ball in flour, then egg, and finally breadcrumbs.
Deep fry the balls until golden-brown and drain on kitchen paper.
Serve the crab balls with the tomato sauce and confit tomatoes.