A land tax accomplishes that, with the activity "under the protection of the state" creating value that is captured by a tax on use of land under the jurisdiction of the state.
Income from overseas investments wouldn't be under the protection of the state where they reside, and appropriately, wouldn't be taxed by the state in which they reside.
On the subject of taxation, almost all of his admonishments were to tax less and less intrusively:
To subject every private family to the odious visits and examination of the tax-gatherers ... would be altogether inconsistent with liberty.
and
“[Governments are] ...without exception, the greatest spendthrifts in the society.”
and
“The agents of [government] regard the wealth of their master as inexhaustible; are careless at what price they buy … at what price they sell.”
and
“Those unproductive hands [in the government] … may consume so great a share … that all the frugality and good conduct of individuals may not be able to compensate … this violent and forced encroachment [of taxation].”
and
Now many such things may be done without intitling the people to rise in arms. A gross, flagrant, and palpable abuse no doubt will do it, as if they should be required to pay a tax equal to half or third of their substance.
and
Little else is requisite to carry a state to the highest degree of opulence from the lowest barbarism but peace, easy taxes, and a tolerable administration of justice: all the rest being brought about by the natural course of things.
and
There is no art which one government sooner learns of another than that of draining money from the pockets of the people.
and
“The profusion of government … [has] retarded the natural progress.”
and
The statesman who should attempt to direct private people in what manner they ought to employ their capitals, would not only load himself with a most unnecessary attention, but assume an authority which could safely be trusted, not only to no single person, but to no council or senate whatever, and which would nowhere be so dangerous as in the hands of a man who had folly and presumption enough to fancy himself fit to exercise it.
His preference for ground rents:
Both ground- rents and the ordinary rent of land are a species of revenue which the owner, in many cases, enjoys without any care or attention of his own. The annual produce of the land and labour of the society, the real wealth and revenue of the great body of the people, might be the same after such a tax as before. Ground-rents, and the ordinary rent of land are, therefore, perhaps the species of revenue which can best bear to have a peculiar tax imposed upon them.