In a small bowl, soak onion in lemon juice for 10 to 15 minutes. Drain, reserving lemon juice.
Meanwhile, preheat a grill or grill pan to medium-high. In a large bowl, toss asparagus with 1 tbsp oil and season with salt and pepper. Add to grill and cook for 2 to 3 minutes per side. Remove from heat and cool to room temperature.
Prepare topping (if using): In a small food processor, pulse cheese and hazelnuts into rough crumbs.
Prepare dressing: In a small bowl, whisk remaining 2 tbsp oil and reserved lemon juice. Season with salt and pepper.
Divide arugula among plates and top with tomatoes, asparagus, onions and dressing, dividing evenly. Garnish with topping.
This quick-cooking chili tastes like it’s been simmering for hours. To get it on the table even faster, you can replace our seasoning mix with 4 tbsp of an all-natural Mexican-style spice blend, but make sure to look for low-sodium varieties.