Salsa Mexicana (Cruda)

Yield:	6 Servings
Categories:	Mexican, Salsa

1	md	Tomato (6 ounces)
4	tb	Finely chopped white onion
2	tb	Roughly chopped fresh coriander
3		Chiles seranos, finely chopped, with seeds
1/2	ts	Salt, or to taste
1/3	c	Cold water