In a medium pot over low-medium heat, melt 2 tbsp of butter. Add 1 cup of orzo and toast, stirring often, until golden brown and nutty-smelling—about 3 minutes.
Carefully pour in 6 cups of boiling water and add a generous pinch of salt. Stir and cook the orzo until al dente, about 8–10 minutes.
In the last minute of cooking, stir in 1 cup of peas to lightly cook them. Frozen peas: 30 seconds to 1 minute, fresh shelled peas: 2–3 minutes, snap peas: 30 seconds.
While the orzo is cooking, make the breadcrumbs. In a separate pan, heat 2 tbsp of olive oil over medium heat. Add 2 minced garlic cloves and sauté for 1 minute, just until fragrant (avoid browning). Add 1 cup of breadcrumbs and toast, stirring frequently, until golden and crispy. Finish with lemon zest and remove from heat.
Once the orzo and peas are cooked, drain and toss with a little olive oil to prevent sticking. Let it cool slightly, then transfer to a serving bowl or platter.
Top with chopped cucumber, avocado, herbs, a drizzle of olive oil, lemon juice, and the garlicky lemon breadcrumbs. Season with salt and pepper to taste.