In a bowl, stir together the soy sauce, rice vinegar, honey and sesame oil. Pat the salmon pieces dry with a paper towel and add to the bowl. Stir to coat. Marinate in the refrigerator for 10 minutes.
Meanwhile, make the spicy sriracha mayo. In a small bowl, stir together the mayonnaise, sweet thai chili sauce, sriracha and water. Add a splash more water, as needed, to thin out the sauce so it can easily be drizzled. Set aside.