Heat olive oil in a large skillet over medium high heat. Add the scallions and sauté for a few minutes. Add the diced radishes to the pan and cook for another 7 to 10 minutes, or until the radishes are tender and start to lose a little bit of color.
Transfer the rinsed black beans to the pan and cook for another few minutes, or until they are warmed through.
While everything is cooking, prepare the avocado crema by combining the avocado flesh, cilantro leaves, lime juice, garlic, sea salt, and olive oil in a food processor or high speed blender. Blend until smooth, about one minute. You may need to add an additional drizzle of olive oil to promote blending. Taste and add more seasonings as desired.
Warm the corn tortillas on a griddle or in a skillet over medium heat just before serving.
Add a large spoonful of the radish and black bean filling to each corn tortilla. Top with avocado crema to taste, and serve with fresh lime wedges. Enjoy!