Heat olive oil in a large skillet; add onions, season with salt and cook for 2 minutes, or until translucent.
Add beef and cook until browned, stirring occasionally; drain.
Return to heat and season meat with cumin, paprika, chili powder, garlic powder, salt and pepper.
Stir in tomatoes and kidney beans.
Add water and bring to a boil.
Lower heat to medium-low and continue to simmer for 7 minutes.
Stir in tortilla wedges.
Add cheese on top and remove from heat.
Cover skillet and let stand for 5 minutes, or until cheese is melted.
Garnish with yogurt or sour cream, avocado, and green onions.