1. Dissolve tamarind pulp in 1/4 cup warm water in a small bowl. Strain through a fine sieve into a larger bowl, pressing pulp with the back of a spoon. Discard pods, but scrape excess pulp clinging to outside of strainer into bowl. Add sugar, fish sauce, lime juice, garlic, and chile; stir until sugar dissolves. Add tomato and onions. Set aside for 1 hour.