How do i get Solar Flare Beam in GW2?

All GW1 abilities (including solar flare beam) and chomp cannon will be found in the wondrous packs of greatness that sell for 35,000.

All original GW2 abilities (excluding chomp cannon) can be gotten from rux for 500,000 each.

These of course excludes the default abilities for each character which the character just starts with.