Cut the salmon and avocado into small 2x2 cm cubes
Mix rice vinegar, sesame oil, soy sauce and lime in a bowl; add salmon and marinate covered for 30 minutes in refrigerator
Cut the melon into a rectangular piece approximately 4 cm high and 10 cm long; slice thinly and layer on plate
Add avocado to marinated salmon and place on top of melon
Garnish with dressing juice