When you use 'the' before a noun, you are referring to a specific instance of that noun. It is a definite article.
'A', an indefinite article refers to a abstract or general version of that noun, basically, it's up to the listener/reader/circumstances to fill in which specific instance (if any) fits that noun.
In your examples:
- The data extracted from a node, yes, correct. The specific data extracted from some node
- A data extracted from .... Incorrect. 'data' is plural, as Roger pointed out in the comments. If you had said A datum extracted from... you would be referring to any one datum extracted. Which datum would depend on context.
- The tea was delicious Correct. A specific tea was delicious
- A tea produced by Ahmad company. Is correct. In this case, you are referring to any one type of tea produced by Ahmad Company. The context would explain more information. For example, if you had: "ABC, a tea produced by Ahmad Company....", you would know which one. On the other hand, "Oh, I'm just drinking a tea produced by Ahmad Company....", would not define which tea.
So in answer to your question, both 'a/an' and 'the' can be used before uncountable nouns, but it is up to the rest of the sentence to determine if that usage is correct or not.
I did a quick search, and this website seems like a good resource for indefinite/definite articles.