In a small skillet, heat 1 teaspoon of the canola oil. Add the onion and garlic clove and cook, stirring gently, for 2 minutes. Season lightly with salt. Discard the garlic clove. Whisk in the cider vinegar and add 1 teaspoon canola oil. Taste for seasoning. Remove from heat and set aside.
Place a large heatproof bowl over low heat and add the remaining 1 tablespoon canola oil. When the bowl is warm remove it from the heat and add the spinach. Season lightly with salt and toss with a spoon so the spinach gets coated with the oil and wilts slightly, 1 minute. The spinach should only be partially wilted and still appear somewhat raw. Pour off any water that might accumulate in the bottom of the bowl from wilting and stir in the onion and dressing from the skillet. Add chopped hard-boiled egg. Serve immediately.
To hard boil eggs, place eggs in a medium-sized pot of cold water and set over high heat. Cook for 11 minutes then remove from pot and run under cold water to cool.