Cut an X in bottom of tomato with sharp paring knife and blanch tomato in 3-quart saucepan of boiling water 10 seconds. Transfer tomato with a slotted spoon into a bowl of ice and cold water and cool. Peel off skin with paring knife and discard. Halve tomato crosswise and seed it, then cut into 1/4 inch dice. Stir together tomato and remaining ingredients. Season salsa with additional salt and pepper if desired.