Halve the zucchini lengthwise, then cut crosswise into 1/4 inch thick half moons.
Cut off and discard the stems of the peppers. Halve lengthwise, then thinly slice crosswise.
Chop garlic and capers.
Remove and discard the stems of the kale and roughly chop the leaves.
In a large pan, heat the ghee and olive oil on medium high heat. Add the sliced zucchini in an even layer. Cook, without stirring, 3 to 4 minutes, or until lightly browned.
Add the cut peppers, garlic, and capers. Season with salt and pepper. Cook, stirring occasionally, 1 to 2 minutes, or until slightly softened.
Add the chopped kale and vinegar to the pan (the vinegar will splatter!). Cook, stirring occasionally, 2 to 3 minutes, or until slightly wilted.
Add 1/4 cup water and cook, stirring occasionally, 3 to 4 minutes, or until kale is wilted and water has cooked off. Serve immediately!