Shrimp and Avocado in Tamarind Sauce

Fry shallot and make tamarind sauce:

Heat oil in a 1-quart heavy saucepan over moderate heat until hot but not smoking, then fry shallot, stirring, until golden brown, about 2 minutes. Transfer with a slotted spoon to paper towels to drain (shallots will crisp as they cool). Reserve oil. Soak tamarind pulp in boiling-hot water in a small bowl until softened, about 5 minutes. Force pulp through a sieve into a bowl, discarding solids. Add sugar, soy sauce, fish sauce, and 1 1/2 tablespoons lime juice and stir until sugar is dissolved. Cut avocados and cook shrimp:

Halve, pit, and peel avocados. Cut into 1 1/2-inch chunks and toss with remaining 1 1/2 tablespoons lime juice in a bowl. Transfer reserved oil to a 12-inch heavy skillet and heat over moderately high heat until hot but not smoking, then sauté ginger, garlic, chiles, and salt, stirring constantly, until fragrant, about 30 seconds. Add shrimp and sauté, turning over once, 2 minutes total. Stir in tamarind mixture and simmer until shrimp are just cooked through, about 2 minutes more. Spoon shrimp and avocado over rice, then sprinkle with peanuts and fried shallot.