In a small mixing bowl, combine the shrimp with olive oil, 1 teaspoon of chili powder, and 1 teaspoon of fresh lime juice. Toss thoroughly to ensure each shrimp is evenly coated with the spices and oil. Heat a small skillet over medium-high heat, then add the shrimp in a single layer and cook for 1 to 2 minutes on each side.

In another small bowl, stir together the mayonnaise, ½ teaspoon of chili powder, and the remaining 1 teaspoon of lime juice. Mix well until smooth and fully blended.

Arrange the phyllo shells on a serving platter. Evenly distribute the shredded lettuce among the shells, creating a fresh, crisp base for the toppings.

Spoon a small dollop of the chili-lime mayonnaise mixture into each shell over the lettuce. Top off with the shrimp, pressing gently so it stays in place.

Serve immediately while still warm. Enjoy as a delightful appetizer or party snack!