Black Bean & Sweet Potato Tostadas

Name: Black Bean & Sweet Potato Tostadas
Prep time: 15 min
Cook time: 25 min
Total time: 40 min
Yield: 4
Ingredients: Ingredients; Sweet Potato Seasoning; 1 teaspoon chili powder; 1/2 teaspoon cumin; 1/2 teaspoon smoked paprika; 1/4 teaspoon cayenne pepper; Salt and pepper to taste; 8 corn tortillas or tostada shells; 2 medium sweet potatoes, peeled and diced (1/2-inch cubes); 1 can (15 oz) black beans, drained and rinsed; 2 tablespoons olive oil, divided; 1 red bell pepper, diced; 1/2 red onion, diced; 3 cloves garlic, minced; 2 cups baby spinach; 1 avocado, sliced; 1/2 cup cotija cheese, crumbled (optional); 1/4 cup pepitas (pumpkin seeds); 1/4 cup fresh cilantro, chopped; Lime wedges for serving; Cilantro Lime Crema; 1/2 cup Greek yogurt or Mexican crema; 2 tablespoons fresh lime juice; 2 tablespoons fresh cilantro, minced; 1 clove garlic, minced; Salt to taste