Whisk cornflour and 560ml water in a bowl to combine; set aside. For chilli paste, place ingredients in a blender and blend to a paste; set aside.
Heat oil in a large heavy-based saucepan over medium-high heat. Cook crab, in batches, turning frequently, until starting to colour (3-5 minutes). Remove crab with a slotted spoon and set aside.
Add chilli paste, ginger and garlic to pan; cook until fragrant (2-3 minutes). Stir in tomato, sugar and cornflour mixture and bring to the boil (5-6 minutes). Return crab to pan; cook partially covered with a lid, turning crab occasionally until cooked through (15-20 minutes). Season and top with sea succulents and blood limes. Serve with damper on the side.
