Heat and stir soup over low heat; add next 4 ingredients and heat.
Beat egg whites till stiff.
Beat egg yolks till thick and lemoncolored; gradually stir in tuna mixture.
Fold into egg whites.
Pour into ungreased 2-quart casserole.
Bake in moderate oven (350°) 30 to 35 minutes or till mixture is set in center.
Serve at once with lemon wedges.