Depends. Alcohol is excreted through kidneys & lungs. So how much is detectable depends on how much was ingested. Both breath & urine can show alcohol for up to 24 hrs, depending on how much, when, state of hydration, like that. So if you are worried about detection of alcohol in your urine, it's best to avoid it altogether. You need to ask yourself if you have a problem with alcohol abuse. See your doctor.
No. Beer is alcoholic beverage therefore it is usually detected by breath analyzer or blood alcohol level.