To make dressing, combine patis, lemon juice, sugar, siling labuyo and shallots. Set aside.
Boil 4 cups of water and pour over the sotanghon. Soak for 10 minutes, then drain the noodles and freshen them with a cold water rinse. Drain the sotanghon well.
In large mixing bowl, put shrimp, sotanghon and dressing. Mix well.
Allow at least 15 minutes before serving so the flavors can blend.
Arrange on serving plates, on a bed of lettuce.
Garnish with wansuy leaves and slices of red tomatoes.