Arrange salmon in 4 corners of 10 inch glass casserole, placing narrow ends of fish toward center .
Melt butter 30 seconds on High in glass measuring cup.
Add lemon juice, stir and pour evenly over salmon.
Sprinkle with salt and pepper to taste.
Top with onion slices and a dash of paprika.
Cover each steak with damp lettuce leaf.
Cook 5 to 7 minutes on High, rotating dish 1/4 turn halfway through cooking time.
Let stand 5 minutes.