Peel and finely chop the onion. Halve the avocado and remove the core. Peel the avocado halves and cut the flesh into small cubes. Wash coriander, shake dry and chop. Halve limes, squeeze juice.
Mix 4 tablespoons lime juice, avocado, onion and coriander. Season to taste with salt, pepper and sugar.
Dab salmon fillet dry, cut into 4 slices and salt lightly. Heat the oil in a coated pan and fry the salmon fillet for 4-5 minutes while turning. When turning, brush the fish with chilli sauce and fry until done.
Arrange salmon fillets on plates, spread avocado salsa on the salmon.