In a large bowl, combine the flour, baking powder, and salt.
Add the vegetable oil or shortening and mix until the mixture resembles coarse crumbs.
Gradually add the warm water, mixing until a smooth dough forms. You may need to adjust the amount of water slightly.
Divide the dough into 8-10 equal portions and roll each portion into a ball.
On a lightly floured surface, roll each ball into a thin tortilla, about 6-8 inches in diameter.
Heat a large skillet or griddle over medium-high heat. Cook each tortilla for about 1-2 minutes on each side, or until lightly browned and cooked through. Keep the cooked tortillas warm in a clean towel.
In a small bowl, mix the refried beans with ground cumin if using. Warm the beans in the microwave or on the stovetop until heated through.
Spread a layer of warm refried beans onto each tortilla.
Top with grated cheese, sour cream or Greek yogurt, diced tomatoes, chopped onions, cilantro, and avocado if using.
Drizzle with hot sauce if desired.
Fold each tortilla in half to create a half-moon shape or roll it up if preferred.
Enjoy your meal!