Heat the vinegar, water, sugar and salt in a small saucepan until sugar and salt is dissolved. Once the sugar has dissolved, remove the pickling liquid from the stove top and allow it to cool while you're preparing the rest of the recipe.
In a large skillet, heat the oil over medium-high and add the chilies and garlic. Sauté, stirring frequently until softened, about 5 minutes. Allow the chilies to cool enough to handle.
Add the chilies and garlic to a sanitized 1-quart sized jar (or 4 smaller mason jars).
Note: If desired, slice some of the chilies in half length-wise in order to infuse the vinegar with chili spice and flavor.
Pour the water/vinegar mixture over the chilis and allow the contents of the jar to cool to room temperature. Seal the jar and refrigerate. Pickled peppers will stay fresh in an air-tight jar for up to 1 month.
Notes
*Replace the olive oil with avocado oil or grapeseed oil.**If you don't do cane sugar, you can use coconut sugar or pure maple syrup.You can also leave the chilies raw and skip the sautéing process, but they will come out more firm.If you're adding the pickling spices, you can toast them in a skillet on the stove top for a few minutes to open up the flavor. Then use a mortar and pestle to mash them before adding them to the jars.