Fill a medium pot with cold water and add potatoes. Bring to a simmer over medium heat, and let cook for about 6 minutes or until the potatoes are tender, but not mushy. Drain the potatoes and set aside.
While the potatoes are cooking, heat a large sauté pan to medium-low heat and add the onion. Cook the onion for 3-4 minutes or until it is tender and translucent. If the onion begins to stick, add some water or vegetable stock to the pan.
Add the garlic and let cook for 2 more minutes. Add greens, and if necessary add more vegetable stock. Mix well.
Once the greens are cooked, add the potatoes, season with salt and pepper and stir. Set aside.
In a medium sauce pot bring one cup of vegetable stock to simmer over medium heat. Add in mole paste and stir with a wooden spoon until the mole paste is dissolved, about 3 – 4 minutes.
Pour in 1 more cup vegetable stock and stir. Once the mole reaches the desired consistency remove from heat. Add as much vegetable stock as necessary.
Wrap the tortillas in a moist paper towel and place in the microwave for 30 seconds. Repeat until the tortillas are warm and flexible.
Take 1 ½ tbsp. of the filling and place it on a tortilla. Fold the tortilla in half over the filling. Repeat until you have filled all the tortillas. (Work fast or everything will get cold!)
Using a large serving spoon, pour mole on each plate and spread to cover the width of the plate. Place 3 filled tortillas on top of the sauce on each plate, then cover with more sauce.
Top with avocado slices, toasted sesame seeds, and vegan cotija. Serve immediately.