Gently mix the tomatoes, avocados, onions, arugula, and half of the vinaigrette in a large bowl. Check for seasoning and add more vinaigrette, if needed. Sprinkle the cumin and cilantro over the top and serve immediately.
Whisk together the lime juice, vinegar, honey, cumin, and cilantro in a medium bowl. Gradually whisk in the oils until emulsified. Season with salt and pepper, to taste. Do not use a blender to make this vinaigrette.