Is Alarplasty/Nostril reduction safe in case of ethnic/thick oily skin type of candidate?

Hello and thank you for your question.  The
best advice you can receive is from an in-person consultation. Alar base reduction and a tip refining rhinoplasty can have a nice result in the right patient.  Alar reduction usually does not have healing issues and should always be closed with minimal tension.   Make sure you specifically look
at before and after pictures of real patients who have had this surgery
performed by your surgeon and evaluate their results.   The most
important aspect is to find a surgeon you are comfortable with. I recommend
that you seek consultation with a qualified board-certified plastic surgeon who
can evaluate you in person.
Best wishes and good luck.
Richard G. Reish, M.D.
Harvard-trained plastic surgeon

Without photos- and the benefit of physical exam- it's difficult to give you the best answer. Generally speaking it's a safe procedure and incision placement is discussed after the initial exam. Be sure to seek an experienced Board Certified PS with extensive experience in Rhinoplasty

Alar excision to reduce alar width usually do heal well.  However it usually is done with some tip and dorsal work to make sure there is adequate balance to the nose.