TO PREPARE: Bring all sauce ingredients to simmer in a medium nonreactive saucepan, stirring to break up the tamarind pulp. Simmer to blend flavors, about 3 minutes. Strain sauce through a fine sieve into a medium nonreactive bowl. Press on the pulp and seeds to release their liquid; discard solids. (Can be cooled, covered, and refrigerated overnight.).
Season tenderloin with salt, pepper, and oregeno. Follow Recipe #222625 to cook your pork tenderloin.