Preheat a grill.
Mix the ground meat with the hot sauce. Form eight 8-ounce burgers.
Season the burgers on the outside with salt and pepper. Transfer them to the grill and sear the burgers with the grill top down. Cook for about 3 to 4 minutes, and then rotate to make grill marks, grilling for about another 2 minutes, each time closing the grill top.
Flip the burgers and grill for about 2 minutes. Rotate for the grill marks and grill an additional 2 minutes. Remove the burgers from the grill onto a plate and rest, away from the heat, for about 5 minutes. This will produce an even, pink burger. Of course if you like it cooked more allow about 3 to 4 more minutes on the grill for each temperature beyond medium-rare that you like.
Top with Marinated Red Onions.
Cut onions into thick rings, about 3/4-inch thick. Keeping the rings intact, place them in a bowl and cover with the vinegar, red wine, and olive oil. Season with salt and pepper. Gently toss to coat. Marinate for at least 30 minutes, or overnight, if needed.
Preheat the grill.
Place the rings on the grill and cook for 3 to 4 minutes on each side. Cool. When cool enough to handle pull the rings apart and use as needed.