Make the dynamite sauce
Preheat the oven to 375°F. Heat 2 tablespoons of the oil in a 12-inch skillet over medium heat. Add the mushrooms to the pan with ¼ teaspoon salt and cook, stirring, until the mushrooms have released their water and look dry, 8 to 9 minutes. Transfer to a large bowl and cool for 5 minutes. Gently fold in the mayo, sriracha, lime juice, sugar, and ¾ teaspoon salt until incorporated. Pat the scallops dry on both sides with paper towels, cut into ½-inch pieces, and gently fold into the mushroom mixture until incorporated.
Build and bake the dish
Combine the rice, cilantro, remaining tablespoon oil, and ½ teaspoon salt in a bowl. Lightly grease four 2-cup oven-safe ramekins, gratin dishes, or mini pots, or do it family-style in one 10-inch cast-iron pan. Add ½ cup rice to each ramekin, then top each with a generous cup of the dynamite mix. Bake, uncovered, until the top is browned and the scallops are just cooked through, 13 to 14 minutes. Garnish with chopped cilantro.
Tip: You can also bake these family-style by layering the rice and dynamite mix in a greased 8 × 10-inch baking dish.