Preheat grill for medium heat and lightly oil grate.
Heat oil in a saucepan over medium heat. Saute onion for about 5 minutes, or until caramelized. Stir in honey and vinegar, and add crushed red pepper, Cajun seasoning, salt, and black pepper. Reduce heat, and simmer 5 minutes, stirring occasionally. Remove from heat, and set aside.
Sprinkle ribs with salt and pepper on both sides. Place ribs on grill rack, cover, and open vents halfway. Cook for 35 minutes, turning ribs once. Brush ribs with sauce, and cook covered for 5 to 10 minutes Turn ribs, cover, and cook for another 5 to 10 minutes. Remove ribs from grill. Heat remaining sauce, and serve together with ribs.
