Light Coals or gas grill for direct heat.
In a large bowl using your hands, combine pork, onion, garlic, curry powder, Worcestershire sauce, and crushed red pepper. Mix well, but be careful not to overwork the meat; this will result in tough burgers. When the ingredients are well combined, divide the meat into 4 equal portions; shape into 4 ¾-inch-thick patties; season with salt and pepper, to taste.
In a small bowl, toss the red onion with oil; coat well.
Brush the grate with an oil coated paper towel. Place the patties over the heat. Cover and grill over medium heat for about 8 to 10 minutes, before turning only once.
After about 6 minutes, of grilling the burgers, add red onion to a grill pan, turning once.
After 8 to 10 minutes, flip the burgers.