Heat oil in a large nonstick skillet over medium heat. Add onion, jalapeno pepper, and garlic; saute 8 minutes. Add shrimp, vinegar, and salt, and saute 3 minutes. Pour tequila into one side of skillet, and ignite tequila with a long match. Let flames die down. Add tomato and cilantro, and cook 2 minutes or until thoroughly heated, stirring occasionally. Remove from heat, and stir in lime juice. Spoon shrimp mixture over rice. Serve with avocado wedges.