Yes you can use adjectives to describe a talent. 'Wonderful talent for cooking' is a good example

Yes, most adjectives would work here. (I think "tremendous" is slightly better than "wonderful," because "tremendous" simply indicates "how much." "Wonderful" suggests something odd, amazing, or surprising). "He has a tremendous talent for cooking." "He has a wonderful talent for cooking." "He has a fantastic talent for cooking." "He has an exceptional talent for cooking." "He has an outstanding talent for cooking." "He has a great talent for cooking." All are fine. Also, of course, you can say "He is a talented cook," "...very talented cook..." "...extremely talented cook..." "...amazingly talented cook..." "...wonderfully talented cook..." and so on. That said, sometimes less is more. You don't say what you are writing. In something like a letter of recommendation, using adjectives and adverbs to strengthen something may not be very helpful. When you've said "He is a talented cook," you've said it all. It is better to strengthen the comment by mentioning other things, particularly verifiable facts. "He is the most talented cook who has ever worked in my restaurant" is stronger than "He is an outstandingly talented cook." "He is a talented cook who has an exceptional ability to improvise when needed" says something about the nature of his talent.