Combine soy sauce, lime juice, honey, sesame oil, and rice vinegar in a bowl to make the dressing; stir until well combined.
Cut off top of the pomelo; score peel using a sharp knife, going about 1/2-inch deep into the peel. Pry peel and pith off the pomelo. Pull apart into 2 halves. Separate segments, peel off membrane, and remove seeds. Break the segments into bite-size pieces.
Toss pomelo with romaine lettuce in a bowl. Top with shrimp; garnish with peanuts and green onion. Drizzle dressing over salad; toss before serving.
You can add crispy fried shallots for a crunchy texture. In a small saucepan, heat 2 tablespoons light olive oil over medium heat. Add thinly sliced shallots and fry until golden and crispy. Transfer to a paper towel to soak up the oil and cool.