In a small food processor or high-speed blender, combine the non-fat Greek yogurt, jalapeño, lime juice, cilantro, and a pinch of the sea salt.
Pulse until the mixture is completely smooth and the jalapeño is finely incorporated, then transfer to a small bowl and chill in the refrigerator.
Heat a large non-stick skillet over medium-high heat and add the ground turkey, breaking it into small crumbles with a spatula.
Cook the turkey until browned and cooked through, then stir in the chili powder, ground cumin, garlic powder, remaining sea salt, and black pepper.
Remove the turkey from the pan and set aside; wipe the pan clean and return to medium heat with the olive oil.
Place the corn tortillas in the pan and cook for 1-2 minutes per side until they are crispy and golden brown.
Fill each crispy tortilla with the seasoned turkey and shredded romaine lettuce.
Drizzle the chilled jalapeño crema over the tacos and serve immediately while the shells are still warm and crunchy.