Spicy Marinated Vegetables and Sardines on Toast

Name: Spicy Marinated Vegetables and Sardines on Toast
Ingredients: 1 1/2 teaspoons coriander seeds; 1/2 teaspoon fennel seeds; 8 small any color carrots (about 6 ounces total), scrubbed; 2 small shallots, peeled; 1 small serrano chile; 1/3 cup sherry vinegar; 6 radishes, trimmed; 2 tablespoons olive oil, plus more for drizzling; 1/2 baguette, split in half lengthwise; 1 garlic clove, peeled; 3/4 cup mayonnaise; 3 (3.75-ounce) cans sardines in water, drained; 1 lemon; A spice mill or mortar and pestle