Preheat the oven to 400 degrees F.
Put the oil and onions in a medium skillet and cook over very low heat, stirring occasionally, until onions
are soft and caramelized, about 15 minutes. Turn the heat up to medium and add the arugula
. Cook until the arugula is wilted, about 1 minute. Season with salt and pepper.
Place the tortillas on a baking sheet and top each with some of the arugula/onion mixture. Crumble some goat cheese on top of each, and bake for 10 minutes. Allow to cool for a few minutes and cut each pizza
into 4 triangles.