Cover the bulgur with water and soak for 30 minutes.
Drain and, a handful at a time, thoroughly squeeze out all liquid.
Place bulgur, onions, salt and pepper in processor and process with on-and-off turns until nearly smooth, scraping down sides as necessary. Transfer to bowl and knead until smooth. Set aside.
Steam fish until just cooked. Flake into small pieces and set aside.
Heat butter in a small skillet then add onion and scallions and saute until onion wilts, 3 to 5 minutes.
Stir in flaked fish, cilantro, cumin and salt and pepper, stirring gently over medium heat 2 minutes.
Set aside and cool completely.
For Tahini Sauce:
Place tahini and a 1/2 cup water in processor or blender; blend until smooth.
Add wine vinegar, garlic and salt and pepper; blend until smooth.
Add enough water to bring sauce to pouring consistency. Transfer to small bowl and stir in parsley.
Set aside, covered, at room temperature.
To assemble, place small bowl if ice water on work surface. Using palms, form golf ball-size balls of bulgur mixture. Dipping fingers in ice water as you work shape each ball into a hollow tube around your index finger, gently pressing mixture into small cigar-shaped tubes about 3 inches long.
Moisten fingers frequently and patch any cracks as you work.
Slip each shell off your finger and fill with about 1 tablespoon of cooled fish filling using a small spoon. Press ends of tubes over fish filling, forming a tight seal.
Cover and freeze until firm, at least 2 hours.
Heat 2 inches of vegetable oil in large saucepan to 375 F.
Fry kobebas until golden, 4 to 5 minutes, turning once.
Serve immediately with tahini sauce.