In a medium sauté pan, heat the olive oil over medium-low heat, add the sliced garlic and cook until golden and crispy, about 4 to 5 minutes. Remove the garlic with a slotted spoon onto a paper-towel-lined plate. In batches, add a few sage leaves to the hot oil and fry until just crisp. Remove with a slotted spoon and place on the paper-towel-lined plate. Reserve the oil. Season the garlic and sage with salt.
Brush the halibut with the garlic-and-sage-scented olive oil. Heat a grill pan to medium-high heat. Grill each side of the fish for 3 to 5 minutes and season with salt and pepper. Remove and top with the reserved garlic and sage chips.