1. Boil the vinegar, sugar and water together in a saucepan. Add the onion and let the mixture cool in the refrigerator.
2. Warm up a grill pan. Remove the woody ends of the asparagus. Sprinkle the vegetables with olive oil. Grill them for 2-3 minutes on each side, then sprinkle with salt and pepper. Keep them warm.
3. Cut slices of Double Crème Blue cheese and place on the toast. Add the grilled vegetables and the pickled red onions. Garnish with fennel tops. Sprinkle with peanuts and serve.
Can be served alone or with grilled meats, such as steak or chicken.