One of the things that's usually on the table when you go to a restaurant here is pickled vegetables. Usually it's carrots and chilies, but it can include all kinds of vegetables from cauliflower to zucchini. It lasts for several weeks in the fridge and is quick and easy to make. It's nice to keep around for tacos, or you can put it on anything that needs some zing.
You can make a lot or a little at the time and use whatever vegetables you want. I like carrots, onions, garlic, and various chilies. Whatever you use, chop them up, then stir-fry them for about 10 minutes. You can use a lot or a little oil- a lot is typical but a little is fine. After they've fried, add some vinegar. You don't have to cover the vegetables, but you want enough vinegar that the vegetables will simmer in it. If that seems too vinegary for you, dilute it with a some water. Also, add some salt, sugar, herbs (Italian seasoning is acceptable, and some bay leaves. Simmer for 5-10 minutes, then cool, bottle, and store in the fridge.