I mean my Question more as a matter of cultural conceptions rather than translation as such.
Coming from the English-speaking (y originalmente no hablaba español en absoluto) side of the equation, it has so far been only a few years since I learned, much to my surprise, that in Spanish (for the most part, at least in Latin America and in Europe), North and South America are not in fact two discrete continents, but rather a single one, generally referred to as, simply, América.
Quite logically, it follows that anyone from any part of [the] America(s) is an American. The trick with this, however, is the fact that, not only in the USA or even exclusively in English, the term "American" typically tends to connote a person specifically from the country called the United States of America.
Both in English and in Spanish, a shortcut around this confusion seems to be the terms Latin America(n\s), hispanoamericanos, and such the like, which cover the vast majority of the non-anglophone parts of América.
But is it at all common for people from América Latina, whether in English or Spanish, to casually refer to themselves simply as "Americans/ americanos" sans any qualifiers and generally without expecting the risk of confusion (unless, say, they come from a Spanish-speaking U.S. territory such as Puerto Rico is)?
Many English-speakers that I know would affirm what seems to be obvious, that someone from a continent called "America" (North, South, Central or however you'd want to parse it) is undoubtedly an American. For the most part though, my understanding and experience is that the conception of "American" as referring exclusively to people from the USA is pervasive enough that I have Canadian friends who are quick to eschew the term, emphasising a distinction between themselves and U.S. citizens, while I have Mexican friends who seem bewildered at the discovery of the idea that in English they are not "Americans" as obviously as they've always been precisely that in Spanish.
Further to that, when hispanohablantes [those among them who are not also English-speakers] hear U.S. citizens referred to as "Americans" and the nation of the USA called simply "America," is that generally a source of confusion for them, since, if I understand the use of the terms correctly, in Spanish these terms equate, not to a single country and its inhabitants alone, but to an entire continent and the constituents thereof? Does it tend to create situations in which one wonders: "Hmmm ... ¿Pero de qué parte del vasto continente americano estamos hablando aquí?"
I recently asked a Mexican and an Argentine this question. They're both fluent in English, though. The Argentine simply said that latinoamericanos understand this terminology as "a mistake" made by people from the USA. Is there anything more to it than that? Or is it just as simple as my Argentinian friend puts it?