Idiom: A day at the beach
Ron and Lisa are both students in the same class in university. It's nearing the end of the term and Ron is stressed about his finals...
Ron: I've been doing research for two days now, and I don't feel any closer to writing my final essay. I wish our professor would just give us a multiple choice exam. That would be far easier for me.
Lisa: No way! I never do well on multiple choice tests; but, for me, writing an essay is like a day at the beach.
Meaning: A day at the beach is a non-stressful, relaxing day - an easy day. When someone uses the idiom a day at the beach, it means the project, task, or event will be easy or non-challenging.