Based on my one ammonia spike experience, I'd say that you can probably kiss your corals goodbye
They, and my snails, were the only things that kicked the bucket. Everything else lived. That being said, I don't have a cucumber and don't know how it reacts to ammonia.... I'd probably pull the tank apart to get it out (I'd be freaking out right about now)... Anywho, your tank looks really great. And, on the picture it looks like the rocks on the left are floating?!?!