Learn Croatian: Ona želi izuti sandale na plaži. - She wants to take off her sandals on the beach.

Croatian has specific verbs for footwear. While you use skinuti for most clothes like a jacket or a hat, you must use izuti when taking off shoes, boots, socks, or sandals. The opposite, putting them on, is obuti.

I've learned that taking off shoes is izuti se. Why is there no se in this sentence?

You use the reflexive se when you don't mention the specific footwear, meaning to take one's own shoes off (for example: Ona se želi izuti). Because this sentence explicitly names the direct object (sandale), the verb is no longer reflexive.

Is sandale in the nominative or accusative case here?

It is in the accusative case because it is the direct object of what she wants to take off. For feminine nouns ending in -a like sandala, the accusative plural ending is -e, which happens to look exactly the same as the nominative plural.

Could I say na plažu instead of na plaži?

Not in this context. Na plaži is in the locative case, showing where the action takes place (she is already at the beach). If you used the accusative na plažu, it would imply motion toward a destination, sounding like she wants to take off her sandals while traveling to the beach.