Heat oil in large skillet over medium heat.
Add diced onion and cook for 3 minutes.
Add minced garlic and cook 1 minute more.
Add ground beef to the skillet carefully.
Cook beef until completely browned, about 8 minutes.
Drain excess fat from the cooked beef.
Add cumin, chili powder, salt, and pepper.
Mix seasonings well and cook 2 minutes.
Warm tortillas in microwave for 30 seconds.
Place beef mixture in center of tortilla.
Sprinkle cheese generously over the beef filling.
Fold bottom edge up over the filling.
Fold sides in toward the center tightly.
Roll up completely to form burrito shape.
Serve immediately while cheese is still melted.