Preheat oven to 350 degrees F. Lightly oil muffin tins and press in wonton wrappers to form cups. Bake cups at 350 for 10-12 minutes until they are browned.
Remove wonton cups and let cool for a few minutes, then remove them from muffin tins and cool completely.
For bean mixture, add butter and onion to a medium pot over medium heat. Cook for 2-3 minutes, then add drained and rinsed pinto beans plus 1/4 cup water. Mash well. Season with salt and pepper.
Make wonton cups by layering: beans, sour cream, salsa, avocado, cheese, jalapeños, and cilantro.
Best to serve immediately, but can make a few hours in advance without worry.