Is it difficult for Iranian citizens to get a tourist visa for the Ukraine. And how is the procedure to get it.
Difficult is subjective, so we'll leave that. However, there is a process, which is easy to find with a google search. However, to help:
You do need a visa as an Iranian citizen applying to visit Ukraine.
Then you just need to apply to a visa company, or the Ukrainian consulate/embassy in Iran, if that exists.
For example, some people use VisaHQ, and indeed, they have an application form on their site for Iranian citizens, along with instructions. You'll need to complete the application, in full, provide credit card details, and mail them the documents.
You also need travel insurance (evidence provided), passport photos and the other required documents asked for on the form.
In conclusion, difficult? No. It's a regular visa application, and provided you have no red flags (previous refusals, etc), it should be a regular process.
You might also need proof of your travel agency if used, or an invite (I had to back in 2008, but I can't see it here. Follow the process and you'll be ok).