Stem the asparagus: at the hard end of the asparagus, start to bend the end until it breaks. This should break off the hard stem. You can also simply use a knife to cut the ends off, but the hard part starts at different points).
Place the asparagus in a 9x13" baking dish and spread out.
Drizzle avocado oil, balsamic vinegar and salt over the asparagus. Mix up a little to get the oil and vinegar on all the pieces.
Bake uncovered in oven at 425F for 15-20 minutes depending on how much asparagus you are cooking. The soft ends of the asparagus will start browning slightly - this is when you know the asparagus is finished.
Remove from oven and stir back into the oil and vinegar. Serve.