Kua rite koe? means: Are you ready.
The tense marker “kua” is a preposed verbal particle which marks the perfect tense. It’s often taught as being used for any sentence that in English would use “have” or “has”.
However, it’s commonly used in sentences where the English translation doesn’t use have/has, although a literal translation might. “Are you ready” in this example could be translated more literally as “Have you prepared?” or “Have you become ready?”
Kua commonly highlights that an action has been completed or something has changed state as a result of some event.
Kua in a conversation normally relates to events that have happened in the past, but this convention is not a rule about kua which only needs to apply to something changing state or being completed: