To prepare the pickled onion, finely cut the red onion and mix with the rest of the ingredients. Leave to macerate for at least two hours before using.
To prepare the pea "guacamole", blanch the peas for 3 or 4 minutes and cool with water. Blend the peas, salt, Tabasco, coriander and lemon juice. Cut the seitan into thin strips and brown with a drop of oil in a pan and heat the tortillas in a pan or the oven.
Assemble the tacos by spreading a layer of seitan on each tortilla and placing a slice of Raclette on top. Lightly grill in the oven and finish with the guacamole and drained pickled onion.
Notes: To melt the cheese, you can place the tacos in a covered pan over a very low heat or use a kitchen torch. Corn tortillas can also be used.