Combine first 7 ingredients in a small mixing bowl. Season with salt and pepper.
Blanch the snow peas for 1 minute in a small pot of boiling water. Drain and rinse under cold water. Pat dry. Slice snow peas lengthwise into 1/4" strips and toss with 1 tablespoon of the olive dressing.
Separate tuna with a fork in a medium bowl. Add 6 tablespoons of the dressing and toss.
Spread insides of the rolls or baguette pieces with the remaining dressing.
On the bottom halves, arrange snow peas, then onion, then tomatoes, tuna. Top tuna with sliced eggs.