In a large skillet, heat over medium heat and add the ground beef and diced onion. Cook until browned and the onion is translucent, about 5–7 minutes. Drain excess grease, then stir in minced garlic, taco seasoning, and salsa, letting it simmer for 3–5 minutes.

Lay each tortilla flat and spread a layer of refried beans if using, then spoon a generous portion of the beef mixture in the center, topping with shredded cheese. Fold the sides of the tortilla inward and roll it up tightly, securing with a toothpick if needed.

For frying, heat vegetable oil in a skillet over medium-high heat until it reaches 350°F. Fry each chimichanga seam-side down for 2–3 minutes until golden, then flip and cook the other side. For baking, preheat oven to 400°F, place chimichangas seam-side down on a greased baking sheet, brush with oil, and bake for 20–25 minutes.

Remove chimichangas from the skillet or oven and let cool for a minute before serving. Serve with toppings like sour cream, guacamole, or salsa.