Answer
Wa `alaykum As-Salamu waRahmatullahi wa Barakatuh.
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
In this fatwa:
If a woman has no choice but to do wudu’ in a place where men are passing by, she can cover herself by having another woman stand in front of her to protect her from passing glances, or with a screen or cover held up by her sister, or she can turn her back on passers-by in such a way that men will not be able to see whatever she uncovers when doing wudu’.
With regard to your question, we would like to cite the following fatwa published on www.islamqa.info:
If a woman has no choice but to do wudu’ in a place where men are passing by, she can cover herself by having another woman stand in front of her to protect her from passing glances, or with a screen or cover held up by her sister, or she can turn her back on passers-by in such a way that men will not be able to see whatever she uncovers when doing wudu’.
As for putting her hand into her sleeve, that will not properly accomplish the washing of the arms, because what is required is for water to flow over the part that is being washed and reach every part of it, and that is not possible if she washes her arms when they are inside the sleeves.
With regard to wiping the head, there is nothing wrong with wiping the front part of the head, then completing the wiping over the head cover, because a concession allowing a woman to wipe over her head cover was granted by a number of the scholars, especially if there is a need to do that.
Allah Almighty knows best.