In a small heat-proof bowl combine carrot and jalapeño. Top with red onion. In a small saucepan combine vinegar, sugar, 2 tsp salt, and 1/4 cup water and bring to a low boil over medium heat, stirring occasionally until salt and sugar have dissolved. Pour over vegetables and set aside to cool.
In a small bowl whisk together 1 tbsp olive oil, lemon juice, garlic, oregano, cayenne pepper, and 1/2 tsp salt. Place portobello mushrooms in a ziplock bag or shallow container and pour over marinade. Cover and leave to marinate for 15 minutes.
When mushrooms are ready heat a grill pan or cast-iron skillet over medium-high heat. Meanwhile, combine pinto beans chipotles in adobo, and 1/4 cup water in a medium saucepan and place over low heat, stir occasionally.
Add mushrooms to grill pan or skillet and cook for 5-6 minutes per side until browned. While mushrooms are cooking brush the inside of sliced bread with remaining 1 tbsp olive oil. Remove mushrooms to a plate and add bread to pan cut-side-down for 2-3 minutes until toasted.
Mash pinto beans with a potato masher or fork. Spread pinto beans onto the bottom halves of bread, top with mushrooms, pickled red onions, cilantro, and top halves of bread. Serve with a side of pickled vegetables.