In a small bowl, combine ground fennel, salt, cumin and black pepper.
In a large skillet over medium-high heat, heat 2 teaspoons of olive oil. Pour 1/2 teaspoon of spices and fennel into a preheated skillet, fry, stirring occasionally, 15 minutes, until golden brown. Pour the fried spices and fennel into a bowl and cover with a paper towel.
In the same skillet, heat the remaining 2 teaspoons of oil. Sprinkle the steak on all sides with the remaining spices and place in a preheated pan. Fry the meat for about 4 minutes on each side. Transfer the fried steak to a cutting board, cover with foil and rest for 10 minutes. Then cut the steak into thin slices.
Apply 2 teaspoons of mayonnaise to each of 4 slices of bread. Place 1/4 of the total meat, 1/4 fennel and 1/4 cup of arugula (arugula) on each slice. Cover with the remaining bread slices. Meat sandwich is ready to serve.