Preheat the oven to 375 degrees F. Coat a 12-cup mini muffin tin with nonstick cooking spray.
Place 1 wonton wrapper into each cup. Press the wontons into the cups with your fingers and spray each wrapper with cooking spray. Bake until they are golden brown, 5 to 6 minutes. Remove from the oven and let cool.
Slice 1/2-inch thick slice from the onion and cut into thirds (reserve the remaining onion for Round 2 Recipe Nicoise Salad with Lemon Garlic Vinaigrette and the Online Round 2 Recipe Ham and Cheese Breakfast Burrito). Into the bowl of a mini food processor, add the onion, ginger, brown mustard, red wine vinegar, crushed red pepper, canola oil, salt, and pepper, and pulse until combined. (If you do not have a mini food processor, finely chop the onion and ginger and whisk together with mustard, vinegar, oil and red pepper flakes.) Place into a bowl with the tuna. Thinly slice 1/2 cup of the snow peas (reserve remaining 1 cup snow peas for Round 2 Recipe Nicoise Salad with Lemon Garlic Vinaigrette) and stir to combine.
Fill each wonton cup with the tuna salad, transfer to a serving platter, and serve immediately.