1Heat oven to 400°F. Spray 1 1/2-quart round casserole with cooking spray.
2In 2-quart saucepan, stir frozen vegetables, tuna, soup, milk, pimientos, relish and lemon juice until well mixed. Heat over medium heat 6 to 8 minutes, stirring occasionally, until vegetables are thawed and mixture is hot and starts to bubble. Pour into casserole.
3In medium bowl, stir Bisquick mix and cold water with fork until soft dough forms; beat vigorously 30 seconds. Drop dough by 4 spoonfuls onto tuna mixture; sprinkle with paprika.
4Bake uncovered 20 to 25 minutes until biscuits are golden brown.