In a blender, puree the first 4 ingredients to make the salsa verde.
In a large skillet, heat the olive oil over medium. Add the onion, garlic, cumin, paprika and oregano. Cook, stirring often, until the onion softens, 3 to 5 minutes. Add the turkey and cook, breaking up with a spoon, until cooked through, 5 to 8 minutes. Season with salt and pepper. Stir in the salsa verde. Simmer, stirring occasionally, until the flavors meld and the sauce thickens, about 30 minutes.
Set out the taco shells, turkey mixture and toppings so people can build their own tacos.