This article by Guillaume Iyenda on the lives of street vendors in Kinshasa’s informal economy is nearly a decade old now, but it doesn’t seem like things have changed that much:
Our research showed that the highest diversity of sales took place between 10 and 12 in the morning. As many households consume only one meal a day, people prefer to do their shopping at this time and then cook a meal that is eaten between 4 and 5 p.m. In the late afternoon, sales are high in what is locally called the wenze ya bitula, the “market of the unsold”. Here, people generally sell all their perishable goods, which they are unable to keep from one day to the next because they lack freezers. As a result, these goods are sold at half price or less. Shoppers who most frequently use these markets are those who consume their one daily meal between 8 and 10 p.m.; most of them have to wait for the main income earner to return from work, bringing back the daily money for the food shopping.
Interesting throughout. He also has a related paper [PDF] on how street food preparation is a primary source of income for many women in Kinshasa whose husbands are disabled or unemployed.