Grab the bell peppers and the jalapeño and carefully remove the stem and the seeds from them. Cut them into juliennes.
Next, add some olive oil into a pan and heat it for a couple of minutes. Add the bell peppers, and jalapeño peppers to the pan and sauté them over medium-high heat for a few minutes or until they soften. Season them with salt & pepper and transfer them to a holding plate. The sauté the mushrooms. We do this separately so that the water from the mushrooms doesn't make the peppers too soft and mushy during cooking.
To a bowl, add the flesh with a bit of salt and pepper and a splash of lime juice. Using a fork or potato masher, mash the avocado until you have a nice consistency of guacamole.
To build the tacos, spread some refried beans over a warmed corn tortilla.
Add some pepper and mushroom mix on top, and squeeze a little lime over that.
Add guacamole.
And finally, add some onions and your favorite salsa.
Serve with your favorite sides!
Notes
Please note that the nutrition data given here is a ballpark figure. Exact data is not possible.