When we light the Shabbos candles we cover our eyes. The reason for this is that lighting Shabbos candles is one of the very few times that we ever do the mitzvah first, and then say the Blessing. Almost always we say the blessing first, and then we do the mitzvah.

     When we say the blessing on the Shabbos candles we bring in Shabbos, and once we bring in Shabbos, we are not allowed to light a fire, so we have to light the candles before we make the blessing.

      We cover our eyes when we say the blessing as if to hide from the fact that the candles are already lit. Then, when we uncover our eyes, it is as if we are seeing the lighted candles for the first time.

     After saying the blessing and before uncovering the eyes is an excellent time to pray for all your needs. It is a peaceful "time of favor."