Preheat oven to 180°C fan-forced. Lightly grease a 12-hole muffin pan (½ cup capacity) with oil spray.
Using a 9cm round cutter, cut out 4 rounds from each tortilla. Press tortilla rounds into greased muffin holes. Spray lightly with oil spray and bake for 12-15 minutes, or until light golden and crisp. Transfer to a wire rack to cool completely.
Meanwhile, whisk the oil, ½ of the lime juice, chipotle, Jalapeno and shallots in a large bowl. Season. Add the tomatoes and coriander. Toss gently to combine.
Coarsely mash the avocado in a bowl with ½ of the lime juice and season. Arrange the tortilla cups on a serving plate or board. Spoon in the avocado mixture and top with the tomato mixture. Serve.