Soak the rice noodles in warm (not boiling) water for 25 to 30 minutes, until they bend easily but still feel firm in the center. Drain.
Whisk the tamarind, fish sauce, brown sugar, water and 1 tsp of the Cajun seasoning in a small bowl until the sugar dissolves.
Toss the shrimp with the remaining 1 tsp Cajun seasoning.
Heat 1 tbsp oil in a large skillet or wok over medium-high heat. Brown the andouille 3 to 4 minutes, then move it to a plate, leaving the drippings.
Sear the shrimp 1 to 2 minutes per side, just until pink, and add them to the plate with the andouille.
Add 1 tbsp oil, the shallot and garlic and stir 30 seconds. Add the drained noodles and the sauce and toss with tongs 2 to 3 minutes, until the noodles soak up the sauce and turn tender. Splash in a little water if they stick.
Push the noodles to one side, add the last 1 tbsp oil, crack in the eggs and scramble until just set, then toss them through the noodles.
Return the shrimp and andouille, add the bean sprouts and green onion pieces, and toss 1 minute more.
Serve topped with peanuts, sliced green onion, a squeeze of lime and a pinch of Cajun seasoning.