Combine the the cream cheese and avocado until creamy. Lay out salmon slices to form a rectangle, overlapping slightly.
Spread with cream cheese mixture and roll up from the wide end. Sprinkle with sesame seeds, cover with plastic wrap and chill roll for at least 4 hours.
Slice roll into 1-inch thick rounds and serve immediately on slices of cucumber with dipping sauce, if desired.
For the sauce, combine all ingredients until sugar is dissolved. Serve with the salmon spirals.