1. In a large glass or plastic bowl, dissolve the sugar, salt, and chili paste in the lime juice.
2. Season with pepper and cumin.
3. Stir in the garlic, onion, tomato, jalapeño and cilantro.
4. Gently mix in the shrimp and then cover. Refrigerate for 4 hours.
5. To serve, drain the excess liquid from the shrimp.
6. Allow to rest at room temperature for 15 minutes and serve in avocado halves.