The UAE labour law outlines information on employee entitlements, employment contracts and disciplinary rules. The law is employer friendly, but it also clearly outlines employee rights. You can download a copy of the document from the Ministry of Labour; the document has not been fully updated for some time but amendments and additions are often posted on the site. Labour unions and strikes are illegal, although there have been protests by labourers in the past.
If you find yourself in the situation where you have not been paid, you can file a case with the UAE Labour Department who will take the necessary action. You could also get a lawyer to deal with the claim on your behalf. Although lawyers are expensive in Dubai, the employer will have to bear the cost if the case is settled in your favour.