Steps
1. Begin by boiling the octopus in salted water for about 30-40 minutes until tender. Drain and let cool.
2. Once cooled, cut the tentacles and brush them with olive oil, seasoning with salt and pepper.
3. Preheat a grill or grill pan over medium-high heat. Grill the octopus for about 2-3 minutes on each side until charred.
4. While grilling, prepare the lemon aioli by mixing mayonnaise, lemon juice, minced garlic, Dijon mustard, and chopped capers in a bowl until smooth.
5. Slice the baguette in half and spread the lemon aioli generously on both sides.
6. Place the grilled octopus on the bottom half of the baguette and top with arugula or mixed greens.
7. Close the sandwich, slice in half, and serve immediately.