Heat oven to 425 degrees F. Spread tortillas onto 2 large baking sheets and coat lightly with nonstick cooking spray. Sprinkle with salt if desired. Bake at 425 degrees F for 12 minutes, flipping halfway, until lightly browned and crisp. Let cool.
Fill a medium-size saucepan with enough water to cover shrimp; bring to a boil. Add 2 tablespoons of the lime juice. Add shrimp and cook for 1 minute. Drain and cool slightly.
Chop shrimp into 1/2-inch pieces. Place in large bowl and add pineapple, tomato, remaining lime juice, jalapeños, oil, hot pepper sauce and salt. Refrigerate at least 30 minutes.
Spread tostadas on one or two serving platters. Top each with a scant 1/4-cup shrimp mixture. Makes 12 tostadas.