Place tomatoes, garlic, and habanero, cut-side down, on a foil-lined baking sheet. Broil 20 minutes or until skins are blistered. Cool and remove skins.
Combine shrimp, mango, jicama, cilantro, and red onion in a medium bowl.
Place tomatoes, garlic, and habanero in a blender, and process until smooth. Add tomato mixture to shrimp mixture; stir to combine. Stir in olive oil. Salt to taste, cover, and chill at least 30 minutes before serving. Top with avocado slices, and serve with tortilla chips.