Warm oil in a skillet over medium heat. Stir in onion, and cook about 2 minutes; then stir in garlic, and cook until onion is soft and translucent. Stir in tomatoes, cilantro, and sugar. Season with cayenne pepper, chili powder, cumin, and ground cinnamon. Cook for 10 minutes. Stir in black beans, and bring to a simmer. Reduce the heat to low, cover, and simmer 1 hour or longer.