。
She slammed the table with her fist — bam.
Literal
She [topic-は] fist [with-で] table [object-を] bam [adverbial-と] hit.
ドン is a sound mimetic for a heavy, blunt impact — fists on tables, doors slamming, bodies hitting walls. Following it with と turns the mimetic into a proper adverb modifying 叩く ('to hit'). This is the standard pattern for mimetics: ドンと叩く, ガンと響く, バタンと閉まる. The 拳で uses the instrumental で ('with one's fist'). The whole sentence packs a satisfying punch — every Japanese reader will hear the thud.