How could anyone not like St. Martin de Porres? What's there not to like? He's the St. Francis Assisi of the Dominican Family. He loves animals, cures, helps people, and exemplifies the virtue of humility.
There's a few stories that add to Martin's fame. One of my favorites is the story about the rats. It seems that the priory was overrun with rats. The prior told Martin to set out poison to get rid of them. Martin, of course, obeyed. But he went outside and talked to the rats. He told them about the poison and told them to stop annoying the prior and he would feed them every day, in the barn. Both ends of the bargain were kept up.
To you Saint Martin de Porres we prayerfully lift up our hearts filled with serene confidence and devotion. Mindful of your unbounded and helpful charity to all levels of society and also of your meekness and humility of heart, we offer our petitions to you. Pour out upon our families the precious gifts of your solicitous and generous intercession; show to the people of every race and every color the paths of unity and of justice; implore from our Father in heaven the coming of his kingdom, so that through mutual benevolence in God men may increase the fruits of grace and merit the rewards of eternal life. Amen.
h/t for the prayer from Father Philip Powell, O.P.