In a medium-sized bowl, add the cornstarch and flour. Using a whisk; gently whisk in the Mountain Valley Sparkling Water until the tempura batter has the consistency of crepe batter. It should be light and airy and not too thick.
Heat a medium-sized pot with oil to 350 degrees. While the oil heats, line a plate or tray with paper towels and set aside.
Working one by one, dip the vegetables and shrimp into the tempura batter, and gently place into the fryer oil. Fry each until the tempura is crispy, about 2 to 3 minutes.
Use a slotted spoon or “spider” to remove the tempura from the oil, and place onto a prepared plate or tray to let drain. Season with salt and pepper, and serve immediately.
Make the Ramp Aïoli
Separate ramp bulbs from the leaves, and dice the bulbs.
Over medium-high heat, add 2 tablespoons oil to saute pan. When the oil starts to shimmer, add ramp bulbs and saute until tender, about 2 to 3 minutes. Remove from heat and cool completely.
In a small pot, bring 3 cups water to a boil. Working quickly, blanch the ramp leaves in the boiling water, about 10 seconds, and use a slotted spoon to transfer them to a bowl of ice water to “shock” the leaves. Let cool a couple minutes and remove leaves from the water. Press in a colander or on paper towels to remove excess water.
Rough chop the leaves. Place in a blender and puree until smooth.
In a small bowl, combine mayonnaise, lemon juice, sauteed ramp leaves, ramp puree, salt, and pepper and mix thoroughly. Adjust seasoning as necessary. Reserve in the refrigerator until ready to use–aïoli lasts up to one week in refrigerator.