In a medium bowl, whisk together flour, cornmeal, nutritional yeast, baking powder, salt, paprika, and a few grinds of pepper. Add the plant milk and whisk to form a smooth batter . Fold in the corn, peas, onion, scallion, and herbs until everything is well coated in batter.
Make the avocado smash. Cut the avocados in half, remove the pit, and scoop the avocado flesh into a medium bowl. Drizzle with the lemon juice and smash with a fork until the desired consistency is reached. Season with the salt and a few grinds of pepper and set aside while you make the fritters.
In a large heavy-bottomed pan, heat the oil over medium heat until it starts to shimmer, about 2 minutes. Using a ¼-cup (60 ml) measure, carefully spoon the batter into the hot oil. Cook until a nice golden color, about 3 minutes on each side.
Serve the fritters hot, topped with the avocado smash, arugula, and cherry tomatoes.