Heat a skillet over medium heat, and add a splash of oil. While heating dice the onion. One skillet is hot, add the onion and cook until transluscent 3-5 minutes.
Add the ground beef to the pan, and cook, stirring occasionally until browned. (Tip: pour out some of the grease if mixture seems oily.)
Add the 1 Tbsp cumin and 1 tsp paprika, and season with salt and pepper to taste.
Serve on warmed flour tortillas, layering beef, and pineapple salsa on top. Serve warm.