I make no pretenses that this is based on some autentico salsa especiale I tasted in a tiny cafe in Zihuatanejo. In fact, this recipe is based entirely on a pineapple I had in my refrigerator that was quickly getting a little too ripe (shopping with a 4 year old means you come home with lots of produce and few plans). But it makes use of the Mexican flavors and produce I find all over southern California — the sweet acidity of pineapple matched by savory onions, chiles and cilantro, all mellowed by avocado and enlivened with the crunch of jicama. (If you’ve never had jicama, it’s a great ingredient. Resembling a large pale brown turnip, it’s a juicy root vegetable that’s very faintly sweet and has a terrific crunch not unlike a water chestnut.) [...]