cook onions for 5 or so minutes, until soft and translucent. add the mushrooms to the pan, and cook for 3 more minutes, until soft and cooked through.
add the kale and cook for 2 more minutes, until soft and the kale is wilted.
add the eggs to the pan and cook for 3-4 more minutes, until the eggs are cooked through.
sprinkle the feta cheese evenly over everything, then remove the pan from the heat and allow to cool before rolling.
scoop ¾ cup of the *cooled* egg/veggie filling onto a 12-inch flour tortilla. sprinkle with ¼ cup of shredded cheese. fold the ends over and roll tightly.
wrap tightly in plastic wrap, and store in a larger meal prep container or freezer bag.