Prepare the pickled onions. In a small bowl, whisk together sugar and red wine vinegar until the sugar is mostly dissolved. Rinse the sliced onions under water, pat dry, then add the onions to the red wine vinegar. Cover and set aside.Boil the shrimp. Fill a large pot with about 2 quarts of water (enough to cover the shrimp) and bring to a boil over high heat. Add 1 tablespoon of salt, squeeze the lemon juice into the water, then add the squeezed lemon. Add the shrimp to the boiling water, give it a quick stir, then cover and remove from the heat. Let the shrimp stand for 8-10 minutes, until the shrimp are just cooked through. Strain the shrimp, discard the water, and refrigerate the shrimp until cool, about 1 hour. You can serve this salad with warm shrimp if you prefer.While the shrimp is cooling, make the vinaigrette. In a small bowl, whisk together oil, white wine vinegar, honey, and orange juice. Taste it! Add honey for sweetness, add more vinegar to extra tang. Make the dressing to your liking.Once the shrimp is cool, assemble the salad in a large salad bowl. Add the mixed greens, tomato, bell pepper, and carrots. Strain the onions from the pickling liquid and add the onions and shrimp. Toss with vinaigrette and serve!