Heat oil in large skillet over medium-high heat. Add onions; cook until soft and translucent, about 7 minutes. Add garlic, paprika and cumin; cook until fragrant, about 30 seconds.
Add ground beef to onion mixture. Cook, stirring and breaking up the meat with a spatula, until cooked through, about 8 minutes. Turn off the heat, add in the steamed, chopped spinach and chopped artichokes, Manchego cheese and season with salt and pepper. Mix skillet together until well combined. Set beef mixture aside to cool.
Heat oven to 375F. Place empanada discs on work surface. Spoon a heaping tablespoon of the meat mixture onto center of dough round. Using a pastry brush, paint edges of dough with egg wash. Fold dough into half-moon shape; gently press down edges and twist down to seal. Repeat until all discs are done.
Divide empanadas among baking sheets, leaving 1 1/2 inch space between each empanada. Brush tops of empanadas with remaining egg wash. Cook until the pastries puff and are golden brown, about 18-20 minutes.