According to the chazon ish simon nun hai, ot vov, a person can squeeze lemon into a utensil for dipping food into it. Is this true? Also, why can’t a person squeeze a lemon into a cup or spoon and then pour it into a drink? Is there a difference?
This is correct. Since squeeing lemons is not sechitah de’oraisah, but only (at most) a rabbinic prohibition (see Mishnah Berurah 320:22), it follows that when one is doing so for the purpose of dipping food into the juice and eating the food, and not for the purpose of drinking, it is not prohibited.
The reason for this leniency is that the lemon juice will be “eaten” (as part of the food), rather than drunk; if it’s being poured into a spoon for the purpose of a drink, the juice will be drunk and not “eaten,” and therefore not permitted (as the Mishnah Berurah and the Chazon Ish explain).