I’ve mostly heard ‘yanks’ in English. I don’t know if Japanese slang specifically has a word for USian foreigners as most situations don’t really care about which country and, if more specificity than ‘foreigner’ is required, it’s usually going to be some adjective/descriptor (loud, rude, skin_color_here, etc. in the case of people being those things).
I’ve mostly heard ‘yanks’ in English. I don’t know if Japanese slang specifically has a word for USian foreigners as most situations don’t really care about which country and, if more specificity than ‘foreigner’ is required, it’s usually going to be some adjective/descriptor (loud, rude, skin_color_here, etc. in the case of people being those things).