In a large bowl, whisk together the flour and salt. Add the vegan butter and use a pastry cutter or your hands to mix until the mixture is crumbly.
Add the cold water and mix until a dough forms. Knead the dough for a few minutes until it's smooth and elastic.
Cover the dough and let it rest in the refrigerator for at least 30 minutes
In a pan, heat the olive oil over medium heat. Add the onion and garlic and cook until the onion is translucent.
Add the spinach and cook until it's wilted. Remove from heat and let it cool.
Once the spinach mixture is cooled, season it with paprika, cumin, chili powder and cayenne pepper (if using). Add salt and pepper. Stir well to combine
Preheat the oven to 375°F (190°C) and line a baking sheet with parchment paper.
On a floured surface, roll out the dough to about 1/8 inch thick. Use a cookie cutter or a glass to cut circles out of the dough.
In a small bowl, mix together the vegan cream cheese and the spinach mixture. Spoon a small amount of the mixture onto each dough circle.
Fold the dough over the filling and use a fork to crimp the edges closed.
Place the empanadas on the prepared baking sheet and bake for 20-25 minutes, or until golden brown. Serve warm.