This sounds like a homework assignment, so you will need to pick out the specific examples yourself. However, I'll give you a few pointers for finding good examples of figurative language in Kaffir Boy.
First, look at the speech of Mark Mathabane's mother and grandmother. Throughout the book, these strong women use tribal stories and proverbs to teach Mathabane how to survive. Their language is rich in metaphor. Their use of figurative language in these characters' speech helps develop the characters, the setting, and the cultural milieu. It also helps to reinforce many of the book's themes.
You may also find figurative language around Mark Mathabane's own dialog. Mathabane, who is called Johannes in the book, rarely uses figurative language when he speaks. However, as a writer, he often describes his speech and actions using similes that help to convey his emotions.