Boil water in the saucepan. Add the Asparagus and cook until they are tender. However, they also be crisp to the bite. Drain the hot water out and put the Asparagus in a pot of cold water for a while so that they cool down.
Take a large resealable plastic bag. Put in it the rice vinegar, soy sauce, vegetable oil, sugar, salt, and pepper. Freshly ground pepper has a great taste and an aroma that makes the whole meal smell much more exciting. Put the Asparagus into this bag and seal it. Place the bag in the refrigerator and let it marinade for complete 24 hours.
The next day before serving, sprinkle the Asparagus with the chopped pecans. Garnish with green onions to give an appealing look. Serve right away and collect all the approving looks.