Contrary to what some believe, primitive accumulation of capital is a process that still happens in modern times. The term “primitive accumulation” makes one think that it was a process of the past, and that it has completed its final stage. This is one of the reasons why Marx rightfully critiques this view in section 8 of Capital, “So-called primitive accumulation”
However, primitive accumulation is a process that happens constantly. Usually through coercion and violence, the bourgeoisie and its petty appendix expropriate the worker of their work, even if that means having them as slaves or torturing them.
For instance, not only the United States has 400,000+ slaves illegally, they also have legal slaves through their prison system, which uses institutionalized slave labor, amounting to 1.3 million (60% of prison population), in total 1.7 million slaves in the US.
The kiosk owner isn´t a petty-bourgeois. The owner is a policeman and part of a right-wing militia that controls parts of Rio de Janeiro.
Petty-bourgeoisie is a class relation, not a profession. The petty-bourgeoisie is a bourgeois in small scale. They usually hire a small quantity of workers, or they work themselves with means of production of their own. Artisan workers can be considered petty-bourgeois as well. They live off the selling of commodities, but not through large-scale means of production.