Note: When slicing an avocado, do not peel it; cut in half and remove pit. Using a paring knife, slice the flesh without cutting through the skin. Scoop out slices with a large spoon.
- 1/2 medium red onion, thinly sliced
- 2 tablespoons plus 1/4 cup freshly squeezed lime juice, from about 3 limes
- 2 teaspoons sugar
- Coarse salt
- 1 jalapeno chile (seeds and ribs removed for less heat, if desired), chopped
- 1 cup lightly packed cilantro leaves
- 1/2 cup olive oil
- 4 avocados, about 8 ounces each, thinly sliced
In a small bowl, combine onion with 2 tablespoons lime juice, 1/2 teaspoon sugar, and 1/4 teaspoon coarse salt; toss to combine. Let lime-marinated onion sit at room temperature until it softens and brightens in color, about 1 hour (up to 1 day, covered and refrigerated).
Make dressing: In a blender, combine remaining 1/4 cup lime juice, jalapeno, cilantro, and remaining 1 1/2 teaspoons sugar; season generously with salt. Blend until smooth. With the motor running, add oil in a steady stream through the feeder opening until incorporated.
Just before serving, slice avocados; arrange on a serving plate. Top with onion; drizzle with dressing.