Blend oil, maple syrup, lemon juice, lemon zest, and salt in a small bowl. Add kamut and pecans. Stir thoroughly and let sit until cooled.
- Assemble salad in a tall, glass bowl: Place 1/3 of the kamut at the bottom, topped by half each of the onions and celery, corn, and watermelon. Repeat.
Add the last 1/3 of the kamut to the top and sprinkle with the remaining 1 Tablespoon of diced green onion.
- Present as a layered salad and toss just before serving.