How to Make It
To prepare patties, preheat grill to medium-high (about 450°F).
Heat oil in large nonstick skillet over medium. Add yellow onion; sauté 8 minutes or until deep golden-brown. Stir in garlic; cook 1 to 2 minutes or until fragrant. Remove pan from heat; let cool, and then chop onion mixture.
Combine onion mixture, cumin, paprika, salt, black pepper, and beef in a large bowl. Divide and shape beef mixture into 8 (1-inch-thick) patties. Press an indentation into the center of each patty with your thumb.
Coat grill grate with cooking spray; place on grill. Place patties on grill grate; cook 3 to 4 minutes on each side for medium-rare or until desired degree of doneness. Reserve 4 cooked patties for Thai Beef-and-Cabbage Salad and Skillet Nacho Dip.
To prepare burgers, combine mayonnaise, bell pepper, and chives in a bowl. Place remaining 4 patties on bottom halves of buns; top evenly with tomato, red onion, arugula, mayonnaise mixture, and top halves of buns.