Place noodles in a large heatproof bowl, cover with boiling water; stand until just tender, drain.
Using a mortar and pestle, or small food processor, crush garlic, chilies and coriander to a paste.
Heat 2 teaspoons of the oil in a wok or large frying pan. Pour egg into wok; cook over medium heat, tilting pan, until almost set. Remove omelette from wok; roll tightly, slice thinly. Lightly fry tofu in batches in wok and place to side.
Heat remaining oil in wok or frying pan, stir-fry onion until soft but not coloured, add paste, tamarind concentrate, brown sugar, lime juice and tofu. Stir fry for 2 minutes or until fragrant.
Add half the nuts, sprouts and shallots; stir fry until sprouts are just wilted.
Add noodles, sauce and juice; stir-fry until hot.
Remove from heat; sprinkle with omelette, cucumber, coriander, mint and remaining nuts, sprouts and shallots over Pad Thai.
Serve with lime wedges.