Chile-Lime Fruit and Shrimp Tostadas

From the garden

• 4 cups ripe tropical fruit (mango, pineapple, papaya, guava and whatever else ripened this week), peeled and cut into half-inch cubes
• 1 hot green chiles, seeded and finely chopped
• ½ small red onion, finely diced
• ½ cup fresh cilantro, chopped

From the pantry

• 1 lb large shrimp, peeled and deveined
• 8 corn tortillas
• 1 avocado, mashed rough with a pinch of salt
• 3 limes
• 1½ tsp chili powder · ancho, or a chile-lime salt blend if there is one in the cupboard
• 2 tbsp neutral oil · divided between the shrimp and the tortillas
• salt · to taste
• black pepper

1. Use fully ripe fruit only. Green pineapple and unripe papaya are harsh throat and gut irritants, unripe passionfruit and its rind are not food at all, and plantain has to be fried or roasted first, because it is never eaten raw.
2. Peel and cube the fruit into a chilled bowl, wearing gloves for mango and for any papaya still showing green, since the peel and sap of both raise an itchy rash in people sensitive to poison ivy or latex. Cut red dragon fruit last, as it stains a board magenta and can harmlessly turn urine pink for a day.
3. Toss the cubed fruit with the juice of two limes, the chili powder, the chopped chile, the red onion, half the cilantro and a good pinch of salt. Let it stand 10 minutes and no longer, so the pieces stay distinct instead of collapsing into juice.
4. Toss the shrimp with 1 tablespoon of the oil, the juice of the last lime and a little salt, then sear or grill over high heat 2 to 3 minutes a side, until just opaque through. Chop into rough pieces and let them cool a moment.
5. Brush the tortillas with the remaining oil and toast them in a dry skillet or a hot oven until crisp and blistered, about 3 minutes a side. A tostada that still bends will go soggy under wet fruit.
6. Spread the avocado over each tostada, pile on the shrimp and then the fruit with its juices, and finish with the last of the cilantro, a pinch of salt and black pepper.