Preheat oven to 350 degrees F.
Wash and dry the sweet potatoes. Place on a parchment lined baking sheet rub with the olive oil, and sprinkle with salt.
Place the baking sheet in the centre of the oven and bake for 60-75 minutes, turning the sweet potato every 10 minutes to ensure evening cooking. Cook until the sweet potatoes are tender. Time will vary based on the size of the sweet potatoes.
Remove the potatoes from the oven and carefully cut in half lengthwise. Using a thin edged, metal measuring spoon or melon baller, carefully scoop out a trench in the center of each half, (leave about ½ inch of sweet potato flesh all around the sweet potato (save the removed sweet potato for mash or hash browns the next day or add to a soup, stew, chili, or curry).
Sprinkle each boat with 1 tablespoon of the spinach, and ½ tablespoon each of the jalapeno, onions, and tomatoes. Push this mixture to the sides to form a well in the middle of the vegetables for the egg. Season with salt & pepper.
Return the stuffed sweet potato halves to the baking sheet and make sure they sit without rocking (if the are tender, this should not be an issue).