Prepare a hot grill fire or heat a grill pan over medium-high heat.
Brush cut sides of avocados, tomato, and onion with oil and place, the place cut side down, on grill or grill pan. Grill until vegetables have grill marks and are lightly charred, 8-10 min. Transfer to a cutting board and let cool slightly.
Scoop avocado into a medium bowl and mash with fork. Dice the tomato and onion, then combine. Stir in lime juice, cilantro, garlic, cumin, and salt. Add salt if necessary.
Serve with Strips Tortilla Chips.