炒鱿鱼 is a colloquial verb-object phrase (离合词) that literally means 'to stir-fry squid' but is widely used as a slang term for firing someone from a job. The metaphor comes from the image of a rolled-up blanket (like squid curls) that workers carried when leaving a job. As a separable verb, you can insert elements between 炒 and 鱿鱼, e.g., 炒了鱿鱼 ('fired someone') or 炒过鱿鱼 ('have fired someone'). It is often used in the passive with 被.