The UEFA Europa-League chasing hosts won for the fifth time in seven fixtures, having scored three times in the opening 18 minutes at San Mames against their mid-table opponents.
Aduriz, Athletic's 36-year-old striker, took his tally for the season to 22, while Muniain also bagged a brace after Mikel San Jose had opening the scoring in just the seventh minute.
The defender's free header from Ander Iturraspe's corner was quickly followed by Muniain's first, which came from a free-kick he managed to whip around Tana on the corner of the wall and into the net.
Pedro Bigas reduced the deficit by nodding in off the post but it was 3-1 in the 18th minute when Aduriz finished off a counter-attack by cleverly lifting the ball over goalkeeper Raul Lizoain from Inaki Williams's pass and stabbing home on the floor.
Muniain volleyed in another after the interval after more poor defending from the visitors and Aduriz got his second moments after Las Palmas kicked off again, having collected a square pass from San Jose.
