Vegan Niçoise Salad Sandwich (Pan Bagnat)

Place potatoes in a steamer basket set in a large saucepan. Add water to saucepan to just below basket. Bring to boiling. Steam, covered, 20 minutes or until tender. Add haricots verts; steam 3 minutes more. 2. In a large bowl whisk together the next six ingredients (through pepper). Add chickpeas and artichoke hearts; toss to combine. 3. Cut demi loaves in half lengthwise. Scoop out some of the interior of the loaves to create open pockets. Arrange potatoes and haricots verts in bottom of baguettes. Spread chickpea mixture over top. Top with onion, tomato, and tarragon. Add top of baguette, pressing gently. Cut sandwiches in half. 4. Heat a panini maker to medium-high. Add sandwiches, in batches if needed; cook 3 to 4 minutes or until sandwiches are toasted and heated through. Serve immediately.