One partial solution to this injustice comes from the regular welfare state that may look at the country's population and simply see some wealthy people, some poor. The state may tax the wealthy and redistribute to the poor, without ever bothering to look at the ancient injustice that caused the inequality.
By simply refusing to look at the historical conflict, and focusing only on the present-day problems, perhaps this could render the injustice something of a non-issue. It does leave all the practical and moral issues associated with welfare states, however, and it leaves the descendants of the invaders with legitimate domination of the land.
Another solution, of sorts, is just some kind of negotiated settlement, perhaps like the Land Acts in 19th century Ireland that gradually shifted ownership from the descendants of the English colonists to the descendants of the native Irish. This, clumsy and unjust as it is, still seems better than the more recent seizure and redistribution of land from white farmers in Zimbabwe.
The whole area is messy, however. Feel free to add your own thoughts in comments below.