@ Javier
A canadian conditional discharge is a criminal record for US immigration purposes. An absolute discharge is not as this is considered deferred adjudication.
Either way, CBP is notorious for not knowing their own immigration laws and will deny almost anyone with a criminal charge whether they were proven innocent, guilty or criminally not responsible. A drunk driving or simple assault charge are the only two offenses that will most likely not bar you entry to the US.
Voyeurism is not an offence in most US states as of yet, neither for the federal government. This will likely change in the future. However, it can be classified under sexual harrassment, intimidation or coercion. According to the most updated version of what is a crime of moral turpitude, sexual harassment is not a CMIT. This will likely change in the coming years. The matter will most likely be settled by US courts. These criminal charges are fairly new and it will take time for states to update their criminal statutes. Coercion and intimidation do fall under CIMTs however.
There is a rule in US immigration law that might work in your favor, the petty offence exception. The offender must only have committed one crime of moral turpitude other than prostitution or drug related, and the maximum sentence that can be imposed cannot exceed more than six months imprisonment if committed in the US. You can do the waiver and hope for Homeland Security to get you a September Letter under these circumstances. There is no guarantees you get a September Letter however.
Another thing that you can do is wait for your conditional discharge to be up, normally you must wait 3 years after the sentencing date. The discharge should be removed automatically but this rarely happens. You need to write personally to the RCMP to remove it from your record and wipe it clean. Another thing you can do is ask the local arresting police force, the police department that arrested you, to do a file destruction on your behalf to wipe out your record including shredding your fingerprints.
Voyeurism is considered pretty serious and will not necessarily destroy all the information but the fingerprints/discharge will be removed from the RCMP database. Certain information can still be obtained however under the Privacy Act, nothing gets really destroyed, just tossed aside from the public. Avoid all travel to the US in the meantime.
If all the info is removed from the RCMP database, CBP cannot see it if they never accessed it before. However, I have reason to believe that if you were issued a new passport after you were discharged, CBP can probably see the info when they scan it, therefore it is important to remove everything before getting one. If asked after by CBP, if you have been arrested, you shouldn't lie but I believe you have enough judgement to know what to answer.
Now, I do except for a certain individual, John Rogers, who posts here constantly to repeat what I stated in subsequent posts claiming that he is "correcting me". Obviously, he is looking for potential clients to expand his waiver business. I believe you are old enough to take the right decisions. He will charge you top dollar. So, I hope I answered all your questions regarding your situation. I do also waivers but I provide info free of charge.