- Cut cucumber lengthwise in half; remove seeds. Cut each half crosswise into thin slices; place in bowl and sprinkle evenly with salt. Let stand 30 minutes; toss occasionally.
- Meanwhile, place fish in single layer in shallow pan; pour in 1/4 cup teriyaki sauce, turning fish over to coat both sides. Marinate 30 minutes; turn over once.
- Rinse cucumber slices, drain and squeeze out excess water; return to bowl and combine with vinegar and remaining 2 Tbsp. teriyaki sauce. Let stand 15 minutes. Stir in sour cream and dill; cover and refrigerate.
- Cook fish on grill 4 to 5 inches from hot coals 3 minutes on each side, or until fish flakes easily with fork; serve with cucumber sauce.