Heat a wok and pour in the cooking oil. Add the garlic and stir-fry until aromatic, then add the bean curd, potatoes, and tomato wedges. Stir briefly, then add the yellow noodles and sauce. Continue stirring until well combined. Adjust the seasoning with sugar and salt to taste.
Add the bean sprouts and stir-fry quickly for 1 more minute. Turn off the heat, dish out the noodles, and garnish with scallions, red chili, and fried shallots. Squeeze lime juice over the noodles before serving.
Notes
You can get fresh yellow noodles from Asian supermarket. Yellow noodles are yellow in color and oily. If you can't find yellow noodles, just use spaghetti.