Combine all ingredients for salsa fresca (ingredients 13-20) and set aside.
Place sweet potatoes in a medium pot and add water to cover. Bring to a boil and simmer for about 6 to 8 minutes, until sweet potatoes are tender. Drain and set aside.
Heat broth, thyme, chili powder, and cumin in a skillet over medium heat. Simmer for 3 minutes.
Add cooked sweet potato, black beans, and jalapeño. Cook for about 5 minutes, stirring carefully. Stir in scallions, lime juice, salt, and black pepper.
Warm tortillas by placing them one by one in a dry skillet over medium heat, turning once, for a total of about 1 to 2 minutes per side. Divide sweet potato mixture evenly over all tortillas and top with about 1/2 cup salsa. Roll tortillas tightly. Serve.