Make the slaw: Combine jicama, red onion, radish, and arugula in a large bowl. Squeeze lime half over the vegetables, drizzle with olive oil, and sprinkle with salt. Toss with your hands until everything is evenly coated. Taste and add more lime juice or salt if needed. Set aside.

Begin cooking mushrooms. Heat olive oil in the largest frying pan you own over high heat. Once oil is very hot, add mushrooms a handful at a time until the bottom of the pan is covered but not crowded. Depending on the size of your pan you may need to do this in batches. If so, divide the oil so you don't use it all at once.

Caramelize mushrooms. Let mushrooms cook, undisturbed, until they are golden brown on the bottom. Give a stir and continue cooking until they are about 80% golden all over. Add the chipotle and salt and cook a minute more. Remove from pan and continue cooking the other batches of mushrooms if your pan is too small to fit all of them at once.

Serve! Pile the mushrooms into the warm tortillas. Top with slaw and avocado slices and enjoy!