Using the tip of a paring knife, cut off a sliver of the skin from the rounded side of each avocado half, so they will lay flat on your serving platter. Score the flesh side of each avocado half in a cross-hatch pattern. Brush the inside of the avocado halves with olive oil and sprinkle with salt and pepper. Place the avocado halves cut-side down on the grill for 1 minute 30 seconds. Turn the avocado halves 90 degrees to get cross-hatch grill marks and cook for another 1 minute 30 seconds. Remove from the grill and place, grilled-side up, on a large platter.
Stir together the tomatoes, garlic, jalapeno, onion, cilantro, vinegar, salt and pepper in a mixing bowl. Set aside for assembly.
Whisk together the sour cream, agave, lime juice and hot sauce in a small mixing bowl to form the crema.
Mound about 2 heaping tablespoons of the vegetable mixture into each avocado half. Drizzle the margarita crema over the avocados. Sprinkle the tortilla chips on top. Serve immediately.