Combine chili powder, paprika, cumin, oregano, salt, and pepper
In a large skillet over medium-high heat, cook ground beef and heart for 5 minutes or until browned. Be sure to stir as it cooks so it cooks evenly
Strain the meat, reserving 3 tbsp of fat in a small sauce pan and discarding the rest. Return the meat to the skillet. Whisk reserved fat together with flour over medium heat to create a roux. Cook until roux begins to brown, then whisk in stock, tomato paste, and vinegar.
Add onion, garlic, and bell pepper and cook for another 5 minutes
Move contents of the pan to the side and add spice mix. Toast spices for 2 minutes then add to meat mixture. (If you feel more comfortable, you can do this step in a small skillet to the side.
Add the roux to blender and puree until pasty, then mix into meat.
Split hot dogs down the middle without cutting all the way through. Brown the dogs on a griddle, frying pan, or preferably a grill.
Add hot dog to bun, split side up. Add a line of mustard. Spoon on preferred amount of Coney sauce, and top with chopped onions.