Preheat a skillet over medium heat and add olive oil.
Sauté red onion, minced jalapeños, tomatoes, cumin, and chili powder for 5 minutes.
Add black beans and cook for 2 more minutes; set aside as avocado salsa base.
Mash avocado in a bowl, then fold in cooked salsa, half the cilantro, and juice of 1 lime.
In a separate skillet, cook beaten eggs until fluffy (avoid overcooking).
Warm corn tortillas in a dry pan until pliable.
Assemble tacos: spread avocado salsa in each tortilla, add eggs, top with Greek yogurt and remaining cilantro.