Rinse the salmon fillet, dry it well, dice it. Clean, wash and finely chop the spring onions.
Mix the fish with the egg, panko, spring onions and lime zest, season with lime juice, salt and pepper. Cover and chill for half an hour.
In the meantime, cut the avocado in half, remove the stone, lift the flesh out of the skin and mash it with a fork with a little lime juice.
Mix with garlic and sour cream, fold in the coriander leaves, season with salt, pepper, chilli flakes and cumin.
Shape the fish mixture into twelve small meatballs, fry them in a pan in the heated oil at medium temperature until golden brown on both sides, drain on kitchen paper.
Halve the tomatoes, remove the seeds, cut the pulp into fine strips. Put a dollop of avocado cream on each meatball, garnish with tomato strips and coriander leaves.