Is it permissible to take a portion of the shop's income to cover salaries in the event that the Jewish employer delays in paying the due wages?

It is permissible to take one's right from an oppressor, provided that one does not exceed the right and is safe from disgrace and punishment. This is the correct view. The proof for this is Allah's saying: "Then punish with an equivalent of that with which you were punished" (Quran 16:126), and His saying: "So transgress against him with an equivalent of that with which he has transgressed against you" (Quran 2:194). The argument for prohibiting taking it, based on the hadith: "Return the trust to the one who entrusted you, and do not betray the one who betrayed you," is not a valid basis for proof, because taking one's right without exceeding it is not betrayal but rather justice for oneself.