Over here in Europe, we are only expected to add jobs/qualifications to our resume that are related to the job we apply for. If you are applying for a job in an office, there is no need to mention you worked in a sandwich bar for example. If it doesn't add value, leave it out. However, if you feel that your previous job adds extra value to your resume, you should add it.

Over here we don't mention to reason why we left our previous job, if they want to know, they'll ask in the interview. If you do add your previous job to your resume, and they ask you about it in the interview, I would advise you to be honest about it but use it to your advantage as much as possible. You should not hide the reason why you got fired, but add that you asked them why they deemed your performance to be poor (so you could learn from it, it's important to emphasis that you are willing to learn) and that they did not answer. Maybe you feel that something else is going on, and that the 'poor performance' was just a bogus reason? However, don't 'shame' your previous employer, it doesn't send out the right message to your (possible) new employer.