Slice the mushrooms, zucchini and artichokes into very thin slices. Slice the red onions into fine julienne and set aside separately from the other vegetables. Dice up the chile pepper, removing the seeds and veins for less heat and set aside.
Just before serving, add the marinade to the bowl of mushrooms and veggies and mix together well. Add the red onions and mayonnaise. Mix it all up. Taste and adjust seasonings Divide up the ceviche into four bowls and garnish with sweet potatoes and white corn.