Grease a 12 cup muffin tin. Add one tablespoon water to each muffin cup. Crack each egg into the muffin cups. Bake for 13 minutes.
On a baking sheet, lay out the 6 English muffins, seperated into halves. Toast in oven for 7 minutes.
In the meantime, mix together the refried beans with the chili powder and cumin powder. Spread on the toasted muffin halves and return to the oven for about 5 minutes, or until beans are warmed.
In a blender or food processor, combine the 2 seeded and peeled avocados, Greek yogurt, cilantro, salt, and zest and juice of the lime until smooth.
To serve: Lay an egg on top of each muffin that has been topped with the refried beans. Sprinkle with a bit of feta cheese. Drizzle with the avocado hollandaise and serve.
Notes
Instead of poaching eggs in the oven, you can poach them in over simmering water.