Fresh Mediterranean Salad

2 tablespoons water

1 teaspoon dried oregano

1 teaspoon freshly ground black pepper

1 teaspoon Dijon mustard

1/2 teaspoon kosher salt

2 garlic cloves, chopped

3 tablespoons extra-virgin olive oil

2 cups sliced fennel bulb (about 1 medium)

1 1/2 cups thinly sliced red onion

1 cup pitted ripe olives, halved

3/4 cup chopped fresh flat-leaf parsley

1/2 cup (2 ounces) crumbled feta cheese

1 (15 1/2-ounce) can cannellini beans, rinsed and drained

6 plum tomatoes, quartered

2 tablespoons sunflower seeds