Toast the bolillo rolls on a comal or griddle over medium heat until lightly golden; remove from heat. Spread 2 tablespoon of refried beans on each slice of bolillo roll. Spoon 1/2 cup of chilaquiles on bottom slice of bolillo roll. Top with 1 to 2 tablespoons of crumbled queso fresco, a drizzling of Mexican crema, and chopped cilantro. Cover with top slice of bolillo roll. Serve with fresh serrano chiles or pickled jalapeños.