Heat unsalted butter in a pan. When butter melts sauté chopped onions and garlic. Add oregano and sauté well. Add baked beans to the pan. Season with salt and crushed black pepper. Mix well. The stuffing for tacos is ready. Place the lettuce leaves in the taco shells. Add the filling. Top the filling with some mayonnaise tomato chilli sauce, and grated cheese. Transfer the tacos to the serving plate. Garnish with chopped jalapenos. Serve tacos with orange juice.