Heat the oil in a pan over medium heat. Add the onion and jalapeño and cook for 2-3 minutes, or until the onion is soft. Add the beans, green chiles, taco seasoning and water. Bring to a boil, then lower heat and simmer while you prep everything else.
Add all of the crema ingredients to a bowl and stir to combine. Taste and adjust seasonings as needed. Set aside.
Heat the tortillas over an open flame, in a pan or in the microwave.
To serve, layer each tortilla with shredded lettuce, beans and lime crema. Top with cilantro and serve with lime wedges.