Trim stem ends from asparagus, then cut spears into 1 1/2-inch pieces.

Heat refined coconut oil in a large skillet over medium heat. Add cremini mushrooms; cook, stirring occasionally, until just tender, 8 to 10 minutes. Stir in asparagus; cook until bright green and tender, 3 to 5 minutes. Add garlic in the last minute of cooking. Season with flaky salt and black pepper.