I can have operation in Lebanon and attend legally in Dubai? Or even I can have operation in Brazil?
The laws of United Arab Emirates, like every other foreign nation would require every company to register before doing business.
However, you can establish a liaison office or enter into a partnership agreement with a Dubai based IT firm who will help you in marketing, selling and building your App services to kick start and such liaison officer will conduct all your businesses like you are there and remit all funds to the parent company in your home country.
I can legally guide you further on this procedure, if you can extend a call to me.