Turkey Tostadas

1 small onion , chopped

1 clove(s) garlic , chopped

1/2 pound(s) ground turkey

1/2 cup(s) prepared red tomato salsa

2 tablespoon(s) cornmeal

1/2 teaspoon(s) ground cumin

24 (2 1/4-inch round) water crackers with cracked pepper

4 large romaine lettuce leaves

1/4 cup(s) coarsely shredded Cheddar cheese

1 small tomato , seeded and sliced into 24 thin strips

24 cilantro leaves Cilantro sprigs