I was wondering, what is the Orthodox equivalent to RCIA, and how long is it?
Andrew, welcome to the forum! As far as I know, there is no unified one-size-fits-it-all procedure of admission into the Orthodox Church. However, because you are 15 (meaning that you are in the "age of reason" already), you will have to become a catechumen - a student who takes a class, so to say, with an ordained Orthodox priest. Call or e-mail this Ukrainian Orthodox parish in your city and ask the priest, what are the rules of catechumenate in that parish and in the UOC-USA generally. Perhaps the priest will schedule a time when you will be able to meet with him and, possibly, with other catechumens. The priest will give you books to read, maybe some audiotapes of videos, and possibly other study material. He will also suggest a Catechism for you. There are several popular Catechisms of the Orthodox faith, for example this, http://www.pravoslavieto.com/docs/eng/Orthodox_Catechism_of_Philaret.htm
, or this, http://www.gocanada.org/catechism/catech.htm
, and several other.
Although there is no rigidly set time for the catechumenate, it should be several months, maybe about a year (although your priest might decide in favor of a shorter period of study). Then you will be baptized and chrismated.
Best wishes to you, and may the Lord illumine your heart and your path to the Truth.
P.S. I am a Ukrainian by my ethnicity, too, like pani Liza Symonenko; if they give you hard time at your Ukie parish, let me know and I'll say a few, er, convincing words to them in our language!